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Second-language acquisition

Second-language acquisition (SLA) is the process through which individuals learn a non-native after establishing proficiency in their (L1), encompassing both naturalistic exposure in immersive environments and formal instruction in educational settings. This interdisciplinary field, rooted in , investigates the cognitive, social, and psychological mechanisms underlying L2 development, distinguishing it from first-language acquisition by its reliance on prior linguistic knowledge and conscious learning strategies. Key aspects include the role of from the L1, the formation of an —a unique, rule-governed system bridging the L1 and L2—and the potential for fossilization, where errors persist despite instruction. The study of SLA emerged in the mid-20th century, evolving from behaviorist views in the 1950s that emphasized habit formation through repetition and reinforcement, as proposed by B.F. Skinner. By the 1960s and 1970s, it shifted toward cognitive and generative perspectives, influenced by Noam Chomsky's theory of universal grammar, which posits innate linguistic structures facilitating L2 learning regardless of age or context. Landmark developments included the interlanguage hypothesis by Larry Selinker in 1972, highlighting learners' systematic errors as evidence of an evolving competence, and error analysis techniques that treated mistakes as insightful data rather than mere failures. Major theories in SLA provide frameworks for understanding acquisition processes. Stephen Krashen's (1981) argues that progress occurs through exposure to comprehensible input slightly beyond the learner's current level (i+1), prioritizing naturalistic acquisition over explicit grammar drills, while his affective filter theory underscores how motivation, anxiety, and self-confidence influence uptake. Complementing this, Long's (1983, 1996) emphasizes negotiated interactions—such as clarifications during conversations—that make input comprehensible and prompt output practice, as supported by Merrill Swain's output hypothesis (1985). Additionally, research on suggests that L2 learners access innate parameters to restructure their linguistic systems, though access may diminish after a around . Factors influencing SLA success are multifaceted and include age, with optimal outcomes often before age 10 due to neuroplasticity differences between early and late bilinguals; motivation, divided into instrumental (practical goals) and integrative (cultural affinity); and aptitude, encompassing phonological sensitivity and memory. Socio-cultural elements, such as immersion in English as a Second Language (ESL) contexts versus English as a Foreign Language (EFL) classrooms, along with personality traits like extraversion and low anxiety, further modulate progress. Empirical studies reveal predictable acquisition orders, such as morphemes like plural -s preceding possessive -'s, consistent across diverse learners, highlighting universal cognitive patterns amid individual variations. Bilingualism confers cognitive benefits, including enhanced executive function, as evidenced in neuroimaging research.

Definitions and Distinctions

Core Definitions

Second-language acquisition (SLA) is the process through which individuals learn a non-native language after having acquired their first language (L1), typically encompassing both naturalistic contexts—where learning arises from immersion in everyday interactions and exposure—and instructed contexts, such as formal classroom environments guided by teachers and curricula. This field of study examines the cognitive, social, and linguistic factors influencing how learners develop proficiency in the target language (TL), which is the specific language they aim to master, often in contrast to their source language (SL or L1), the native tongue that serves as the foundation for prior linguistic knowledge. A central concept in SLA is interlanguage (IL), the unique, evolving linguistic system that learners construct, distinct from both their L1 and the TL, characterized by systematic rules, approximations, and potential stabilization short of native-like accuracy. In SLA research, a key distinction exists between competence—the underlying, internalized knowledge of the TL's grammatical rules, vocabulary, and structures that enables comprehension and production—and performance, the observable application of that knowledge in real-time use, which may be hindered by factors like fatigue, anxiety, or limited processing capacity. This dichotomy, originally proposed by in 1965 to describe native speakers' idealized linguistic knowledge versus actual usage, has been adapted to SLA to analyze why learners' output often deviates from their implicit understanding, emphasizing the study of internal grammars over surface errors. Stephen Krashen's input hypothesis further refines this by arguing that competence develops subconsciously through exposure to comprehensible input—language input that learners understand, aided by context—specifically at the level of i+1, where i represents the learner's current competence and +1 introduces structures just beyond it, promoting natural progression without explicit instruction. The term "second-language acquisition" and the establishment of SLA as a distinct interdisciplinary field gained prominence in the , building on earlier linguistic and psychological inquiries but crystallized through seminal contributions like Larry Selinker's 1972 introduction of , which shifted focus from error correction to the systematic nature of learner languages. Selinker's work, alongside influences from Chomsky's , marked a departure from behaviorist views of language learning as mere habit formation, instead viewing SLA as a creative process involving unique learner systems.

Second vs. Foreign Language Acquisition

Second-language acquisition refers to the process by which learners acquire a target in an environment where that is actively spoken and used in daily life, often through and naturalistic interactions. This context typically arises for immigrants or individuals relocating to a where the target serves as the primary medium of communication, enabling frequent exposure to authentic usage. In contrast, foreign-language acquisition occurs in settings where the target is not the dominant or native tongue, such as formal instruction in the learner's home , with minimal opportunities for real-world application outside structured lessons. The primary implication of these contexts lies in the nature and quantity of input learners receive: second-language acquisition benefits from abundant naturalistic input, which includes unscripted conversations, , and social interactions that promote subconscious and fluency development. Foreign-language acquisition, however, relies on limited and controlled input, often decontextualized and focused on explicit rules, which can constrain spontaneous use and lead to slower progress in . This difference in exposure shapes motivational factors, as second-language learners may experience higher instrumental motivation due to practical needs, while foreign-language learners often rely on integrative or academic incentives. Representative examples illustrate these distinctions. Hispanic immigrants acquiring English as a engage with the target language through workplace interactions, community services, and ing, fostering rapid oral proficiency despite varying literacy rates. Conversely, Japanese high students learning English as a primarily encounter it in settings within , where the language holds limited everyday utility, resulting in stronger receptive skills but challenges in production due to infrequent naturalistic practice.

Historical Development

Early Theories and Studies

The foundational theories of second-language acquisition (SLA) in the mid-20th century were shaped by the (CAH), articulated by Robert Lado in his 1957 book Linguistics Across Cultures. This hypothesis assumed that difficulties and errors in learning a target (TL) primarily stem from structural differences between the learner's (L1) and the TL, while similarities facilitate acquisition. Lado advocated for systematic linguistic comparisons to predict , positing that "those elements that are similar to [the learner's] mother tongue will be simple for him, and those elements that are different will be difficult". The CAH influenced early language teaching by prioritizing contrastive descriptions to anticipate and mitigate L1-based errors, though it later faced criticism for overemphasizing . Dominating SLA research in the 1950s and 1960s, behaviorist theories framed language learning as mechanical habit formation, drawing from B.F. Skinner's stimulus-response-reinforcement model outlined in (1957). This behaviorist dominance began to wane following Noam Chomsky's influential 1959 review of Skinner's , which critiqued the stimulus-response model and advocated for innate mental structures in language, setting the stage for cognitive approaches in SLA. Proponents like Charles C. Fries argued that L2 acquisition involves replacing L1 verbal habits with TL patterns through repeated practice, minimizing conscious rule learning. This perspective underpinned the audiolingual method, which relied on mimicry of native-speaker dialogues, pattern drills, and oral repetition to build automaticity, as detailed in Fries' Teaching and Learning English as a Foreign Language (1945). Classroom techniques emphasized error-free production via positive reinforcement, viewing deviations as signs of incomplete habit overwriting rather than creative exploration. A key early empirical contribution came from S. Pit Corder's 1967 paper "The Significance of Learner's Errors," which introduced error analysis as a method to study learner output systematically. Challenging the CAH and behaviorist focus on L1 , Corder contended that errors reveal the learner's unique, rule-governed —a dynamic system constructed independently, much like children's first-language acquisition. He emphasized that learners follow an internal "built-in syllabus" of developmental sequences, with errors serving as "signs that the learner is investigating the system of the new language" rather than mere relics of old habits. This work shifted inquiry toward viewing learners as active hypothesis-testers, paving the way for more learner-centered analyses. Pidgin and creole studies offered valuable parallels to processes, highlighting how simplified contact varieties emerge under restricted input. Derek Bickerton's 1977 chapter "Pidginization and Creolization: Language Acquisition and Language Universals" in Pidgin and Creole Linguistics (ed. Albert Valdman) argued that pidginization resembles second-language learning with limited input, while involves innate linguistic mechanisms for elaboration, analogizing the development of learner interlanguages through simplification strategies like morphological and invariant forms in early . These insights from contact linguistics underscored universal tendencies in language under imperfect learning conditions.

Evolution of SLA Research

The field of second-language acquisition () emerged as a distinct interdisciplinary area of study in the , departing from earlier behaviorist foundations that emphasized habit formation through repetition and reinforcement. This shift was catalyzed by Larry Selinker's 1972 interlanguage hypothesis, which posited that learners develop a unique, rule-governed system distinct from both their (L1) and the target (L2), characterized by systematic errors, creative construction, and potential fossilization. Selinker's framework encouraged researchers to view learner language as an evolving entity worthy of empirical investigation, laying the groundwork for SLA as an autonomous discipline separate from first-language acquisition studies. A key milestone in this period was the establishment of the journal Studies in Second Language Acquisition in 1978, which provided a dedicated platform for publishing research and fostering scholarly dialogue. By the 1980s, SLA research transitioned toward cognitive and psycholinguistic paradigms, emphasizing internal mental processes over external conditioning. This era incorporated Noam Chomsky's universal grammar (UG) theory, suggesting that innate linguistic principles guide L2 development, with researchers like Lydia White exploring how adult learners access UG parameters to form L2 grammars. Complementary to UG, input processing models gained traction, focusing on how learners parse and interpret L2 input to build grammatical knowledge, as advanced in works by Michael Long on interaction and negotiation of meaning. Empirical methods evolved significantly, with increased adoption of longitudinal studies to track individual learner progress over time, revealing developmental sequences and variability in acquisition trajectories. These approaches highlighted the role of cognitive mechanisms, such as attention and , in processing L2 input and output. In the , research broadened to integrate sociocultural perspectives, drawing on Lev Vygotsky's (ZPD) to examine how social interactions scaffold language learning. Pioneering applications by James P. Lantolf and Aneta Pavlenko emphasized mediation through collaborative activities, , and cultural tools, positioning development as a socially situated process rather than purely individual . This integration expanded methodological diversity, incorporating ethnographic and qualitative analyses alongside quantitative data from longitudinal designs, and underscored the interplay between individual agency and communal contexts in achieving proficiency. By the early 2000s, these multifaceted strands had solidified as a mature field, blending cognitive, linguistic, and social dimensions to inform and theory.

Comparisons to First-Language Acquisition

Similarities in Processes

Research in second-language acquisition (SLA) has identified several parallels in the underlying processes of first-language (L1) and second-language (L2) learning, suggesting shared cognitive mechanisms that guide language development across learners. One key similarity lies in the posited role of an innate language faculty, often conceptualized through Noam Chomsky's theory of (UG), which includes the (LAD). This innate endowment is believed to provide humans with universal that facilitate , operating similarly in both L1 and L2 contexts by constraining the hypotheses learners form about target language structures. Although access to UG in adult L2 learners remains debated, empirical studies support its influence in guiding L2 development akin to L1 processes. A prominent example of shared developmental sequences is the natural order hypothesis proposed by Heidi Dulay and Marina Burt, based on their analysis of acquisition in child learners of English. Their 1974 study of - and Chinese-speaking children revealed a consistent acquisition order for 11 English functors (e.g., progressive -ing acquired before plural -s, which precedes possessive 's), independent of the learners' L1 backgrounds. This sequence closely mirrors patterns observed in L1 English acquisition, indicating that learners follow universal developmental paths rather than L1-determined orders. Over 87% of errors in these learners were developmental—systematic deviations typical of emerging grammars—rather than from the L1 (only 4.7%), paralleling error patterns in L1 children who overgeneralize rules like adding -ed to all verbs before mastering irregular past tenses. Such evidence underscores that both L1 and L2 acquisition involve hypothesis-testing stages where learners construct and refine internal grammars through similar error-driven progression. The role of input and interaction further highlights process similarities, as both L1 and L2 learners rely on comprehensible input to advance their proficiency. Stephen Krashen's Input Hypothesis posits that language acquisition occurs when learners are exposed to input slightly beyond their current competence (i+1), allowing subconscious assimilation of structures without explicit instruction—a mechanism akin to how L1 children acquire through caregiver interactions featuring simplified speech (e.g., slower pace, higher repetition, and contextual cues). In L2 contexts, this is evidenced by "foreigner talk" or teacher adjustments that make input understandable, promoting the same hypothesis-testing as in L1, where interaction provides feedback on form-meaning connections. Both processes also feature a silent period, during which learners process input before producing output, building competence through comprehension rather than immediate imitation. These parallels suggest that input-driven mechanisms are fundamental to learning, irrespective of whether it is the first or subsequent .

Key Differences and Critical Period Hypothesis

Second-language acquisition (SLA) differs from first-language acquisition (L1A) in several key ways, primarily due to biological and experiential constraints that limit the ease and completeness of learning after . One foundational concept explaining these differences is the (CPH), proposed by Eric Lenneberg, which posits a biologically determined window—typically from early infancy to around —during which occurs effortlessly and leads to native-like proficiency. This period is thought to close as cerebral lateralization and other maturational processes reduce neural plasticity, making subsequent language learning more effortful and less complete. Supporting evidence comes from cases of extreme deprivation, such as that of , a isolated until age 13, who failed to develop full grammatical competence despite intensive intervention, demonstrating the consequences of missing the critical window for L1A and the even greater challenges for beyond it. A major divergence lies in learning mechanisms: children acquiring languages implicitly through and , relying on subconscious detection, whereas adult learners predominantly use explicit strategies, such as rule and metalinguistic , to compensate for diminished implicit processing capacity. This shift reflects age-related changes in cognitive processing, where adults leverage declarative memory for but struggle with the proceduralization needed for , unlike children's more holistic, input-driven approach. Neuroimaging studies further illuminate these constraints, revealing reduced brain in adults for phonological aspects of , with less activation in left-hemisphere perisylvian areas associated with sound processing, compared to preserved adaptability in and semantics regions. For instance, functional MRI show that late learners exhibit recruitment of auditory and motor areas for novel phonemes, indicating a narrower window of plasticity for than for higher-level structures. These differences manifest in ultimate attainment gaps, where native-like proficiency is rarer in SLA, particularly in , as adult learners rarely achieve the accentless speech typical of early acquirers. According to the Speech Learning Model, post-critical-period learners form less precise phonetic categories due to interference from entrenched L1 representations, leading to persistent foreign accents even among highly proficient individuals. While some late learners attain near-native , phonological mastery remains elusive for most, underscoring the CPH's implications for SLA outcomes.

Characteristics of Learner Language

Interlanguage and Developmental Stages

refers to the evolving linguistic system that second language learners construct, distinct from both their first language (L1) and the target (L2). This system is dynamic, rule-governed, and systematic, producing deviations that are not mere performance errors but reflections of an internal grammar unique to the learner. The term "" was coined by Larry Selinker in 1972, who posited it as a separate linguistic entity influenced by the L1 yet operating independently with its own creative processes and strategies. Selinker's framework emphasized that most adult learners do not achieve full target-like , highlighting the structured nature of this intermediate system. Development in second language acquisition unfolds through predictable stages, as described in the Natural Approach by and Tracy Terrell. The stage, often called the silent period, involves primarily listening and comprehension without much output, lasting from weeks to months. Early production follows, with learners using one- or two-word phrases and basic of around 1,000 words. In the speech emergence stage, learners form short sentences, ask simple questions, and handle basic , expanding to 3,000 words. Intermediate brings more complex structures, abstract topics, and improved accuracy over 3–5 years. Advanced fluency approximates native-like proficiency, though full mastery may take 5–10 years or more. Interlanguage exhibits several key characteristics during development. Overgeneralization occurs when learners extend a beyond its scope, such as applying the regular past tense -ed to irregular verbs, resulting in forms like "goed" for "went." Simplification involves reducing target language complexity, such as omitting articles or copulas to facilitate communication. U-shaped learning curves characterize this progression, where initial correct forms (e.g., rote-learned ) give way to errors from overgeneralization, followed by recovery as nuanced rules are acquired. Fossilization marks the cessation of interlanguage development, where non-target forms stabilize and resist correction despite continued exposure. Selinker (1972) introduced this concept to account for persistent errors in adult learners' output, attributing it to factors like incomplete rule formation. Output in interlanguage can vary by social context or task demands, though the core system remains rule-based.

Sequences in Morphology and Syntax

Research in second-language acquisition has identified consistent sequences in the development of and , often independent of the learner's . Pioneering studies by Dulay and Burt examined the acquisition of English grammatical morphemes among child learners with and as L1s, revealing a "" in which structures like the present progressive (-ing) emerge before the marker (-s). This order, replicated across diverse L1 backgrounds, suggested universal developmental patterns rather than L1 as the primary driver, with morphemes such as possessive 's and irregular past tenses following in a predictable . Longitudinal studies further illuminate syntactic sequences, particularly in question formation and construction. In question formation, learners typically progress from uninverted declaratives, such as "You are going?", to auxiliary inversion like "Are you going?", and eventually to full questions ("Do you go?"), as observed in detailed tracking of individual learners over time. For , acquisition follows a -object , with relatives (e.g., "the man who runs") appearing before object relatives (e.g., "the man whom I saw"), reflecting hierarchical processing constraints in emergent syntax. These patterns emerge gradually in the learner's , building complexity through stages of approximation to target forms. Cross-linguistic evidence supports the universality of these sequences, with similar orders observed in the acquisition of and in languages like and . In as a second language, developmental stages for structures such as placement and positioning mirror those in English, progressing from canonical to non-canonical word orders regardless of L1. For L2 learners, sequences in placement and tense show consistent hierarchies, such as mastery of before subjunctive, indicating shared cognitive mechanisms across Romance and . This convergence points to underlying universals in how learners process grammatical information. The Teachability Hypothesis, proposed by Pienemann, posits that formal instruction can only facilitate acquisition of a target structure if the learner has reached the preceding developmental stage, as processing readiness determines learnability. Empirical tests in instructed settings confirm that attempting to teach structures beyond a learner's current stage yields limited gains, while aligning instruction with readiness accelerates progress in both morphological and syntactic domains.

Variability and Fossilization

Fossilization refers to the stabilization and persistence of non-target-like features in a learner's , even after prolonged exposure to the second language and opportunities for correction. This phenomenon, first conceptualized by Larry Selinker in his paper on , highlights how adult second-language learners often cease progress toward native-like competence, with only a small percentage achieving it fully. A classic example is the fossilization of first-language accents in , where learners consistently apply L1 phonological rules, such as substituting /θ/ with /t/ in English for speakers, despite targeted practice. Fossilization manifests in two primary forms: temporary and permanent. Temporary fossilization involves reversible plateaus that can be overcome with renewed input or instruction, whereas permanent fossilization represents an irreversible end-state where features become entrenched. It also occurs at individual and group levels; individual fossilization pertains to unique, persistent errors in a single learner's output, such as idiosyncratic lexical choices, while group fossilization describes shared stabilizations across learners with similar linguistic backgrounds, like common article omissions among speakers of article-less languages learning English. Several causes underlie fossilization. Insufficient input, particularly when it lacks saliency or variety, prevents learners from internalizing target forms, allowing approximations to solidify. Lack of diminishes sustained engagement, reducing the cognitive effort needed to override established patterns. Additionally, social identity reinforcement can perpetuate fossilized features, as learners may retain L1-influenced speech to maintain ties with their cultural or ethnic . Longitudinal studies confirm the prevalence of fossilization, particularly among advanced learners. Selinker's observation that most learners stabilize short of native competence has been supported by extended research tracking development over years, revealing persistent deviations in areas like and for a significant portion of advanced users. For instance, Donna Lardiere's longitudinal analysis of a learner of English (Patty) documented persistent low suppliance of marking at around 34%, despite ample exposure over a decade. Variability in learner output can act as a precursor to fossilization, with inconsistent errors potentially hardening into fixed patterns.

Role of Language Transfer

Types of Transfer: Positive and Negative

In second-language acquisition, language transfer refers to the influence of a learner's (L1) on the target language (TL), manifesting as either positive or negative effects. Positive transfer occurs when similarities between the L1 and TL facilitate learning, allowing learners to apply existing knowledge effectively to new linguistic structures or elements. This phenomenon was central to the Contrastive Analysis Hypothesis proposed by Robert Lado, who argued that structural parallels between languages promote accurate and efficient acquisition. For instance, speakers of , such as or , often experience accelerated lexical acquisition in English due to cognates—words with shared etymological roots—like "" (English) and "information" (French), which enable quicker vocabulary recognition and production. Such facilitative effects are particularly evident in areas of shared or syntax, where L1 patterns align closely with TL norms, reducing during early exposure. Conversely, negative , also known as , arises when differences between the L1 and TL lead to errors or deviations in the learner's . Lado's framework highlighted that these discrepancies predict potential difficulties, as learners impose L1 rules onto the TL, resulting in non-target-like forms. A classic grammatical example is speakers overusing definite articles in English, such as saying "I go to the " instead of "I go to school," because requires articles with institutions (e.g., "voy a la escuela"). Phonological is similarly prominent, as seen in learners of English struggling with the /r/-/l/ distinction—lacking this contrast in , they may pronounce "" as [rait] or "right" indistinctly, leading to persistent errors. Pragmatic further illustrates negative effects, where L1 cultural norms influence TL communication; for example, speakers may employ overly indirect or formulaic strategies in English requests, diverging from native English preferences for balanced directness. Negative transfer tends to be more frequent and salient in the initial stages of acquisition, when L1 reliance is strongest, but diminishes as proficiency increases and learners develop greater awareness of TL-specific rules. Terence Odlin's comprehensive analysis underscores that while positive supports overall progress, negative instances often highlight cross-linguistic contrasts, informing pedagogical strategies to mitigate . These transfer types operate through underlying psycholinguistic mechanisms, such as of L1 schemas during TL , though their outcomes vary by linguistic domain and learner experience.

Cross-Linguistic Influence Mechanisms

Cross-linguistic influence (CLI) in second-language acquisition often manifests at the interfaces between linguistic modules, where elements from the (L1) interact with target language () processing. At the lexicon-syntax interface, L1 lexical items can intrude into , particularly evident in code-switching behaviors where bilinguals alternate languages mid-utterance, leading to hybrid constructions that reflect L1 syntactic preferences embedded within lexical choices. Similarly, at the phonology-perception interface, L1 speech categories shape perception, causing learners to misperceive or recategorize phonemes based on L1 phonetic inventories, such as learners of English confusing /b/ and /v/ due to the lack of phonemic distinction in . CLI is not unidirectional; the can bidirectionally affect the L1, resulting in attrition-induced changes where prolonged leads to of L1 proficiency, such as simplified L1 syntax or lexical retrieval difficulties in immigrant populations. For instance, studies of Japanese-English bilinguals show TL manner-of-motion verbs influencing L1 gesture-speech encoding, demonstrating mutual permeability between languages. These bidirectional effects highlight how CLI operates through dynamic interactions rather than static L1 dominance. Theoretical models explain CLI variability through perceptual factors. Kellerman's (1983) transferability model posits that L1 transfer likelihood depends on learners' subjective assessment of typological distance between L1 and TL, as well as feature salience; structures perceived as universal or highly marked are less transferable, while those seen as L1-specific are more likely to influence TL production. This perceptual lens accounts for why positive transfer (facilitation, e.g., shared vocabulary roots) and negative transfer (, e.g., L1 errors) occur selectively rather than uniformly. Empirical evidence for CLI mechanisms comes from priming experiments, which reveal automatic L1 during TL production. In cross-linguistic syntactic priming tasks, Dutch-English bilinguals exhibit priming effects from L1 to TL structures, indicating shared abstract syntactic representations that facilitate or hinder TL output based on L1 experience. These non-selective activations underscore the involuntary nature of CLI, where L1 nodes remain accessible and influence TL processing even in proficient bilinguals.

Factors Influencing Acquisition

Linguistic Factors

Linguistic factors in second language acquisition refer to inherent properties of the target language and its relation to the learner's that influence the ease, speed, and patterns of learning. These factors include structural similarities or differences between languages, the of specific linguistic features, and the prominence of elements in the input, all of which shape how learners process and acquire new forms without relying on cognitive or social mechanisms. Typological distance, or the degree of structural similarity between the first language (L1) and the target (L2), significantly affects acquisition outcomes, with closer typologies facilitating faster and more accurate learning. For instance, speakers of , which shares Germanic roots and syntactic patterns with English, typically acquire English more readily than speakers of , a typologically distant language with analytic structure, tonal system, and different . This effect arises because shared typological features reduce the in mapping L1 knowledge to L2 structures, leading to fewer errors and quicker proficiency gains. on psychotypology, the learner's perceived linguistic , further supports that subjective awareness of similarity enhances transfer of lexical and grammatical knowledge. Markedness theory posits that unmarked linguistic structures—those considered simpler or more universal across languages—are acquired earlier and with greater ease than marked ones, which involve additional complexity or exceptions. In and , learners tend to master unmarked forms first, such as basic verbs before irregular past tenses or simple declarative sentences before complex embeddings. For example, English learners often produce correct markings on nouns (unmarked in many languages) prior to struggling with marked gender agreements in languages like . This hierarchy reflects universal principles of linguistic economy, where marked features require more explicit input and practice to override L1 biases. Empirical studies confirm that markedness differential hypothesis predicts acquisition order, with from L1 markedness patterns complicating L2 marked structures. Input saliency, the perceptual or frequency-based prominence of linguistic features in the target language input, determines how readily learners notice and internalize them, with highly elements accelerating acquisition. Features that stand out phonologically (e.g., stress patterns) or morphologically (e.g., frequent affixes) are processed faster than subtle or low-frequency ones, such as clitics or . High-frequency items in naturalistic input, like common vocabulary or prosodic cues, thus promote earlier mastery compared to rare or perceptually opaque structures. This factor interacts briefly with , as L2 features can override L1 interference more effectively. Selective attention models in emphasize that salience enhances cue competition resolution, leading to robust form-meaning mappings. The U.S. (FSI) categorizes languages by difficulty for English speakers based on linguistic properties like and , providing empirical estimates of acquisition time under intensive training. Category I languages, typologically close to English (e.g., , with shared Romance vocabulary and syntax), require 24-30 weeks (600-750 hours) for general professional proficiency. In contrast, Category IV languages, distant and highly (e.g., , with root-based , , and ), demand 88 weeks (2,200 hours). These rankings incorporate saliency of input features and typological distance, illustrating how linguistic factors scale learning effort across languages.

Cognitive and Psychological Factors

Cognitive and psychological factors play a pivotal role in second-language acquisition () by influencing how learners process, retain, and integrate new linguistic information. These internal mental processes determine the efficiency of language learning, with individual differences in cognitive capacities affecting the ability to handle complex and . For instance, capacity, a key cognitive component, supports the simultaneous processing and storage of linguistic elements during comprehension and production tasks. Working memory, often modeled as a multicomponent system, includes subsystems like the phonological loop, which temporarily holds verbal information, and the central executive, which coordinates and manipulation of that information. In , higher working memory capacity facilitates the processing of complex grammatical structures, such as relative clauses, by allowing learners to maintain and integrate multiple elements in . Seminal models from the , including those by Miyake and colleagues, emphasize the phonological loop's role in vocabulary acquisition, where it aids in rehearsing and linking new words to existing knowledge, thereby enhancing retention and recall. Empirical studies show that learners with greater working memory span perform better in tasks requiring syntactic , underscoring its impact on overall proficiency development. Metacognitive strategies further shape SLA by enabling learners to regulate their own learning processes through planning, monitoring, and evaluation. These strategies involve assessing one's during input exposure, adjusting approaches to tasks, and reflecting on progress to optimize future efforts. In , metacognitive awareness allows second-language learners to set specific goals, such as targeting weak areas in , and monitor their strategy use, leading to more autonomous and effective acquisition. highlights that training in these strategies improves outcomes in and , as learners become better at identifying gaps in understanding and selecting appropriate cognitive tools. Psychological factors, particularly affective states, can either facilitate or hinder SLA by modulating the intake of linguistic input. Krashen's affective filter hypothesis posits that emotions like anxiety act as a mental barrier, reducing the amount of comprehensible input that reaches the when levels are high. Low or self-confidence raises this , blocking acquisition, while positive attitudes lower it, promoting deeper and of new forms. This framework explains why learners in low-anxiety environments, such as supportive classrooms, exhibit faster progress in naturalistic settings. Attention and noticing represent essential cognitive prerequisites for SLA, as learners must consciously register linguistic features to convert input into intake. Schmidt's noticing hypothesis asserts that acquisition occurs only when learners attend to and notice discrepancies between their interlanguage and target forms, making awareness the necessary condition for learning. For example, explicit instruction that directs attention to morphological markers, like past tense endings, enhances their incorporation into the learner's system. Without this focused noticing, even abundant input remains ineffective, highlighting attention's gatekeeping role in cognitive processing.

Social and Cultural Factors

Social and cultural factors play a pivotal role in second language acquisition (SLA) by shaping learners' interactions, , and access to the target language (TL) through external environmental influences. These factors extend beyond individual cognition to encompass communal dynamics, where learners negotiate their positions within broader social structures. In particular, theories such as highlight how speakers adjust their linguistic behaviors to align with or distance from interlocutors, influencing the quality and frequency of TL exposure. Similarly, concepts of and underscore how learners' social positioning determines their commitment to language learning, while power imbalances in colonial or post-colonial contexts can either hinder or propel acquisition efforts. Participation in communities of practice further facilitates SLA by embedding learning in authentic social interactions. Communication accommodation theory, originally proposed by Howard Giles, posits that individuals adapt their speech patterns—such as accent, speech rate, or vocabulary—to converge with or diverge from conversation partners, thereby fostering or asserting group boundaries. In SLA contexts, this theory explains why learners may modify their TL production to match native speakers, enhancing mutual understanding and positive evaluations, which in turn encourages sustained interaction and improved proficiency. For instance, converging accommodations can lead to greater TL input and practice opportunities, while divergence might occur when learners resist to preserve ethnic . Empirical studies applying this framework to second language settings demonstrate that such adjustments are not merely stylistic but strategically tied to social goals, impacting acquisition outcomes through enhanced . Learners' identities and their in the TL are deeply intertwined with social positioning, as articulated by Bonny Norton, who argues that language learning is a site of struggle over and power relations. refers to the socially and historically constructed relationship of learners to the TL, where acquisition is driven not just by instrumental needs but by the potential for learners to claim new and resources. For example, immigrant learners may invest heavily in the TL if it aligns with aspirations for , leading to greater engagement and progress; conversely, marginalization can reduce investment and stall development. This perspective shifts focus from innate to how societal structures enable or constrain learners' access to TL-speaking communities, emphasizing that proficiency emerges from active participation in identity negotiation. Power dynamics, particularly in colonial language learning contexts, profoundly influence attitudes toward the TL and overall acquisition trajectories. Robert Phillipson's concept of linguistic imperialism illustrates how dominant languages like English are imposed through historical colonial structures, creating asymmetrical power relations that affect learner motivation and access. In post-colonial settings, such dynamics can foster ambivalence: learners may view the TL as a tool for economic advancement while resenting its association with cultural erasure, leading to varied acquisition patterns. Studies in these contexts reveal that positive attitudes toward the colonizer's language correlate with faster progress, but resistance rooted in anti-colonial sentiments can result in selective or minimal engagement. These imbalances highlight the need to address equity in SLA to mitigate barriers imposed by historical power structures. Participation in communities of practice (CoPs), as conceptualized by Jean Lave and Etienne , accelerates SLA by allowing learners to engage in legitimate peripheral participation, gradually moving from novice observers to full members through shared activities in TL-using groups. In a CoP, learning is situated in social interactions where expertise is distributed, and newcomers acquire the TL via collaborative problem-solving and modeling by more proficient members. For SLA, this manifests in settings like immigrant support networks or hobby clubs, where repeated exposure to authentic language use embeds grammatical and pragmatic knowledge contextually. Research applying this framework shows that such in CoPs enhances fluency and more effectively than isolated study, as learners internalize norms through ongoing and .

Individual Variation

Age and Critical Periods

The role of age in second language acquisition () is a central topic, with research indicating that younger learners generally achieve higher ultimate proficiency, particularly in naturalistic settings, though the patterns vary by linguistic domain. Sensitive periods, or optimal windows for acquisition, differ across language components: shows a relatively early closure in (birth to approximately 6 years), when learners exposed before this point are more likely to attain native-like ; has a later window, typically ending around (up to 15 years), beyond which native-like grammatical intuition becomes rarer; and exhibits minimal age-related decline, allowing effective growth throughout life. These differential effects highlight that while biological maturation influences , the impact is not uniform, with perceptual and articulatory aspects of sound systems proving most vulnerable to later starts. Empirical studies support the possibility of native-like attainment in even after , though it is exceptional rather than typical. For instance, analyses of highly proficient late learners demonstrate that post-pubertal acquisition can yield near-native syntactic processing, but such cases are infrequent, with proficiency correlating negatively with age of onset beyond . The , initially formulated for development, posits analogous maturational constraints in , where exposure timing relative to biological milestones determines ease of acquisition. Starting age profoundly shapes learning processes: early starters, often children under 7, excel in implicit learning, absorbing patterns through without conscious rule analysis, leading to more intuitive in and syntax. In contrast, late starters, typically adults, leverage explicit strategies, rapidly acquiring rules via declarative but struggling with in and complex . This shift underscores how age modulates reliance on versus conscious mechanisms. Adults compensate for diminished implicit learning by drawing on declarative memory systems to memorize grammar rules and exceptions, enabling functional proficiency despite non-native accents or occasional errors. Such mechanisms allow older learners to achieve , particularly in and , though they rarely match the seamless integration seen in early acquirers.

Learner and

Learner aptitude refers to the innate or developed cognitive abilities that predict success in second-language acquisition (SLA). Pioneering work by John B. Carroll in the 1960s identified four key components of language aptitude through factor analysis of performance data from intensive foreign language training programs: phonetic coding ability, which involves the capacity to identify and remember unfamiliar sounds; grammatical sensitivity, the ability to recognize the grammatical function of words in sentences; rote memory for linguistic material; and inductive language learning ability, the skill in inferring rules from language samples. These components were operationalized in the Modern Language Aptitude Test (MLAT), a battery of assessments designed to forecast learning outcomes in formal settings, with empirical validation showing correlations typically ranging from 0.3 to 0.6 between MLAT scores and proficiency gains. Motivation plays a central role in sustaining effort and engagement in , often categorized into integrative and orientations. Integrative , as conceptualized by Robert C. Gardner, reflects a desire to integrate into the target language community and identify with its speakers, fostering positive attitudes toward the language and . In contrast, stems from practical incentives, such as advancement or academic requirements, driving goal-oriented learning without necessarily involving cultural affinity. Research within Gardner's socio-educational model demonstrates that integrative tends to correlate more strongly with long-term proficiency through moderate positive associations, though both types can interact to enhance persistence, particularly in contexts. Self-efficacy, drawn from Albert Bandura's , represents learners' confidence in their ability to perform language tasks, significantly influencing persistence and achievement in . Higher self-efficacy beliefs lead to greater effort, to setbacks, and proactive strategies, with meta-analyses showing moderate positive associations (r ≈ 0.48) between L2 self-efficacy and proficiency outcomes. For instance, learners who perceive themselves as capable of mastering or are more likely to sustain over time, even amid challenges. Twin studies provide evidence for a genetic basis to language , with estimates for second-language learning ability ranging from 30% to 70% depending on the linguistic and method. These figures indicate that while environmental factors like remain crucial, genetic influences account for a substantial portion of variance in , such as in acquisition or grammatical processing. Such interacts modestly with age effects, where younger learners may benefit more from innate predispositions during sensitive periods.

Multilingualism and Prior Language Knowledge

Multilingual learners often exhibit accelerated acquisition of a target (TL) due to the cumulative effects of prior knowledge, which fosters enhanced metalinguistic awareness. This awareness enables learners to analyze and manipulate linguistic structures more effectively across languages, leading to improved problem-solving in , , and during TL learning. Studies indicate that multilinguals outperform monolinguals and even bilinguals in tasks requiring explicit linguistic , such as error correction and rule formulation, attributing this to the dynamic of multiple linguistic systems. Typological proximity between previously acquired languages and the TL further facilitates in multilingual contexts, where intermediate languages serve as bridges for positive . For instance, learners with English as a (L1) and as a (L2) demonstrate faster progress in acquiring as a third language (L3) compared to those without the intermediate Romance , due to shared morphological and syntactic features. This proximity enhances perception of similarities, reducing and promoting efficient mapping of L3 elements onto familiar patterns from closer prior languages. Research on trilingualism highlights additive effects from bilingualism on L3 acquisition, particularly in size and . Cenoz's 2003 study on Basque-Spanish bilinguals learning English as L3 found that bilingual participants achieved higher proficiency levels than monolingual counterparts, with advantages in lexical access and stemming from prior multilingual experience. These findings underscore how accumulated language knowledge creates a scaffold for subsequent learning, extending general transfer principles to multilingual scenarios. Despite these benefits, can introduce challenges through increased from multiple prior languages, often manifesting in during TL production. Learners may inadvertently blend elements from L1, L2, and TL, leading to temporary disruptions in accuracy and coherence, especially in early stages of acquisition. This heightened cross-linguistic activation requires greater to suppress irrelevant influences, potentially slowing initial progress in highly similar language constellations.

Instructional Contexts

Classroom-Based Acquisition

Classroom-based acquisition refers to the structured learning of a within formal educational settings, where is systematically organized to facilitate among learners. These environments emphasize controlled to linguistic input and opportunities for practice, often guided by educators to address diverse learner needs. highlights that such settings enable targeted progression in through deliberate pedagogical strategies. Curriculum design in classroom-based second language acquisition typically centers on the four core skills—, speaking, reading, and writing—with an emphasis on balanced exposure to ensure integrated . This approach recognizes the interconnected nature of these skills, where proficiency in one supports gains in others; for instance, listening exercises often precede speaking tasks to build before . Seminal frameworks advocate for curricula that allocate equal to receptive skills ( and reading) and productive skills (speaking and writing), promoting holistic competence rather than isolated drills. Error correction plays a pivotal role in classroom settings, with debates centering on the timing of —immediate versus delayed—and its impact on learner . Immediate , provided right after an , can enhance short-term accuracy by reinforcing correct forms during the of , though it may increase learner anxiety and disrupt . In contrast, delayed , given after a task or session, allows learners to self-monitor and process errors more reflectively, potentially leading to better long-term retention, as evidenced by meta-analyses showing varied effectiveness depending on task type and learner proficiency. Studies indicate that while immediate correction aids immediate , delayed strategies foster deeper without overwhelming the learning flow. Group dynamics in classroom-based acquisition are enhanced through peer interaction, which fosters collaborative learning by encouraging mutual support and negotiation of meaning. Peer interactions create authentic communicative opportunities, where learners co-construct knowledge, provide informal feedback, and build confidence in using the target language. Research on foreign language classrooms demonstrates that effective group work involves balanced participation, with emergent leadership and equitable turn-taking promoting higher engagement and linguistic gains compared to individual activities. These dynamics are particularly impactful in diverse classrooms, where cultural exchanges enrich the learning process. Assessment in classroom-based second language acquisition commonly employs proficiency scales such as the Common European Framework of Reference for Languages (CEFR), which delineates progress across six levels from (basic user) to (proficient user). This framework measures in the four skills, enabling standardized evaluation of learners' abilities to handle real-world tasks at increasing complexity. CEFR-aligned assessments track advancement by focusing on descriptors like vocabulary range, grammatical accuracy, and interactional fluency, providing educators with tools to tailor instruction and learners with clear benchmarks for achievement.

Naturalistic vs. Formal Settings

Second-language acquisition occurs in diverse environments, broadly categorized as naturalistic or formal settings, each influencing the pace, depth, and nature of learning differently. Naturalistic settings involve unstructured in the target through everyday interactions, such as living abroad or engaging in community activities, where learners receive authentic input without explicit instruction. This exposure promotes rapid development of conversational fluency and intuitive use, as learners focus on meaning-making in real-world contexts, often leading to faster oral proficiency gains compared to structured environments. However, such settings typically result in gaps in formal skills and explicit grammatical knowledge, as the emphasis is on implicit learning rather than systematic . In contrast, formal settings, such as classroom-based instruction, provide structured lessons with deliberate focus on rules, , and correction, often through textbooks and teacher-led activities. These environments enhance accuracy in and , enabling learners to develop metalinguistic awareness that supports precise rule application and writing proficiency. Studies indicate that formal instruction accelerates the rate of acquiring complex grammatical features, like rules in , allowing learners to reach higher proficiency levels in shorter periods than in purely naturalistic contexts, though the underlying developmental sequence remains similar across settings. Despite these advantages, formal settings often yield slower progress in spontaneous and may prioritize over automatic performance. The outcomes of these settings highlight distinct strengths: naturalistic acquisition excels in fostering pragmatic competence, such as appropriate use of speech acts in social interactions, due to the richness of contextual cues and negotiation of meaning in authentic exchanges. Formal settings, meanwhile, build stronger foundations in metalinguistic , aiding long-term accuracy and , but can limit exposure to varied pragmatic nuances without supplementary . For instance, naturalistic learners often achieve high accuracy in implicit tasks through extended , while formal learners benefit from targeted feedback that boosts output modification rates, as evidenced by studies reporting rates around 31% in response to signals. Hybrid models, such as (CLIL), integrate naturalistic exposure with formal elements by teaching subject content through the target language, balancing fluency with structured input. In CLIL programs, learners often outperform traditional formal groups in overall , while also improving content comprehension without significant overload. This approach leverages the strengths of both environments, enhancing pragmatic application in content discussions and grammatical accuracy through integrated tasks, making it particularly effective for sustained acquisition in educational contexts.

Teaching Methodologies and Input

One of the foundational concepts in second-language acquisition instruction is the comprehensible input hypothesis, proposed by , which posits that learners acquire language most effectively through exposure to input that is understandable but slightly beyond their current proficiency level, denoted as "i+1," where "i" represents the learner's existing competence. This approach emphasizes that acquisition occurs subconsciously via meaningful communication rather than explicit rule learning, with optimal input being rich in context and supported by non-linguistic cues to ensure comprehension. Empirical studies have shown that providing such graded input in settings leads to improved grammatical accuracy and fluency over time, particularly when input is voluminous and varied. Task-based language teaching (TBLT) represents another evidence-based methodology that structures lessons around meaning-focused tasks designed to promote authentic interaction and language use. In TBLT, tasks such as role-plays, problem-solving activities, or information-gap exercises encourage learners to negotiate meaning, thereby enhancing without prioritizing form initially. Research indicates that TBLT improves speaking proficiency and engagement, with systematic reviews demonstrating moderate to large effect sizes on lexical and syntactic development when tasks are sequenced from pre-task planning to post-task reflection. For instance, in EFL contexts, TBLT has been linked to increased risk-taking in oral production and greater linguistic complexity in output. Complementing input-focused approaches, the output hypothesis, developed by Merrill Swain, argues that learners benefit from producing language that pushes them to notice gaps in their knowledge, thereby refining their system. Known as "pushed output," this involves tasks requiring learners to express ideas beyond their current abilities, such as defending opinions or describing complex scenarios, which fosters hypothesis-testing and metalinguistic awareness. Studies support that such output production, especially in interactive settings, enhances accuracy in morphosyntax and retention, with evidence from programs showing that accelerates development when combined with feedback. In the 2020s, systems () have gained prominence as a technique for optimizing input exposure through algorithmically scheduled reviews that counteract forgetting curves. tools present or grammatical items at increasing intervals based on learner performance, promoting long-term retention; a of 48 experiments found spaced practice yields a moderate (d = 0.58) on second-language and learning compared to massed practice. Similarly, flipped classrooms invert traditional instruction by having learners engage with input materials, such as videos or readings, outside class, reserving in-class time for interactive tasks and clarification. A 2025 of flipped learning in contexts revealed significant gains in proficiency outcomes (Hedges' g = 0.45), particularly in speaking and skills, with stronger effects in higher-education settings where self-paced input preparation enhances classroom interaction. These methods underscore the importance of high-quality, targeted input in formal instructional contexts to support acquisition.

Theoretical Perspectives

Behaviorist and Structural Approaches

The behaviorist perspective on second-language acquisition (SLA) posits that learning a new involves the formation of habits through stimulus-response associations, reinforced by external , much like first- but requiring more deliberate practice to overcome native- interference. This approach, dominant in the mid-20th century, drew from psychological theories emphasizing behaviors over internal mental processes, viewing as a set of conditioned responses acquired via repetition and reward. B.F. Skinner's 1957 book provided a foundational framework by analyzing language as , where verbal responses are shaped and maintained through from the listener or environment. In this model, second-language learners build proficiency by associating specific stimuli (e.g., a question) with reinforced responses (e.g., an appropriate reply), gradually patterns to automate them without reliance on or conscious rules. Skinner's ideas influenced by suggesting that errors could be extinguished through positive of correct habits, prioritizing and over creative expression. The , emerging from U.S. military language training during and peaking in the 1950s–1960s, operationalized behaviorist principles through intensive oral drills and pattern practice to foster in speaking and listening. Learners engaged in repetitive dialogues, substitution drills, and exercises to internalize structural patterns of the target language, with the goal of to prevent native-language ; for instance, speakers learning English might drill "I am going to the store" variations to habituate verb forms. This method assumed that mirrors habit formation in skill-based learning, such as , and emphasized correction as immediate to shape fluent, error-free production. Structural linguistics complemented behaviorism through contrastive analysis, formalized by Robert Lado in his 1957 work Linguistics Across Cultures, which hypothesized that difficulties in SLA arise primarily from differences between the learner's first language (L1) and target language (L2) structures. By systematically comparing phonological, grammatical, and lexical elements—e.g., English article usage versus their absence in Russian—educators could predict and preempt interference errors, such as overgeneralizing L1 word order in L2 sentences. This approach informed syllabus design, prioritizing high-contrast areas for targeted drills to build new habits atop L1 foundations. Despite its influence, behaviorist and structural approaches faced significant critiques for inadequately explaining learner creativity and variability in . often overpredicted errors, failing to account for "intralingual" mistakes stemming from the target language's own rules rather than L1 transfer, such as English learners incorrectly pluralizing uncountable nouns like "informations" based on overgeneralization. Additionally, the emphasis on immediate imitation overlooked the "silent period" observed in many and learners, where precedes production without reinforcement-driven output, suggesting acquisition involves more than habit formation. These limitations highlighted the approaches' neglect of cognitive and developmental processes in language use.

Nativist and Universal Grammar Theories

Nativist theories of second-language acquisition () posit that humans possess an innate biological endowment for language, enabling the acquisition of linguistic structures beyond what environmental input alone can provide. Central to this perspective is Noam Chomsky's concept of (UG), which hypothesizes a genetically determined set of principles underlying all human languages. In UG, core principles—such as structure dependency and subjacency—are invariant across languages and constrain possible grammars, while parameters represent binary options (e.g., head-initial vs. head-final directionality) that are set during first-language (L1) acquisition based on exposure. This framework contrasts with behaviorist approaches, which emphasize habit formation through environmental conditioning without invoking innate mechanisms. In SLA, nativist theories propose that L1 parameter settings transfer to the initial state of L2 learning, requiring resetting to align with the target language. For instance, learners whose L1 has verb-object word order may initially produce similar structures in L2 English (object-verb) before resetting the parameter to verb-object. The UG hypothesis suggests this process is guided by innate principles, allowing learners to hypothesize and test grammatical rules efficiently despite limited or imperfect input. Seminal work by Lydia White argues that UG facilitates the acquisition of complex syntax in L2, such as binding principles, by providing a universal template that L1 knowledge interacts with. Similarly, Suzanne Flynn's parameter-setting model demonstrates how L2 learners can generalize parameter values across structures, as seen in experiments where Japanese speakers (head-final L1) rapidly adjust to English relative clause placement. A key debate within nativist SLA research concerns the extent of UG access in adults: the "full access" hypothesis maintains that learners retain complete access to UG principles and parameters, enabling parameter resetting akin to L1 acquisition, while the "no access" view posits that UG is unavailable post-critical period, with L2 relying on L1 transfer and general cognition. Proponents of full access, including and , cite evidence from learners achieving native-like competence in UG-constrained phenomena despite non-optimal input. In contrast, researchers like Meisel in the 1990s argued for no UG access in adult SLA, pointing to persistent L1 influence and failure to reset certain parameters, such as pro-drop in non-pro-drop languages. Supporting evidence for UG's role draws from the "poverty of the stimulus" argument adapted to adult learners, where input is often insufficient or inconsistent for acquiring subtle syntactic constraints, yet learners converge on target grammars. For example, studies on English infinitives show adult learners correctly avoiding ungrammatical in embedded contexts (e.g., *John wants Mary to not go) without explicit negative evidence, implying innate UG constraints rather than . This mirrors L1 acquisition patterns, suggesting continuity in the language faculty. Variants like the Full Transfer/Full Access model refine strong continuity by proposing that initial grammars fully transfer L1 settings but retain full UG for subsequent adjustments.

Interactionist and Usage-Based Models

Interactionist models of second language acquisition (SLA) emphasize the role of social interaction in facilitating language learning, particularly through the negotiation of meaning during conversations. Michael Long's , first proposed in the 1980s and revised in 1996, posits that comprehensible input becomes more effective when learners engage in interactive exchanges that highlight comprehension problems, leading to adjustments in the input that make it more attuned to the learner's needs. These interactions, such as recasts and clarifications, provide opportunities for learners to notice linguistic gaps and receive implicit or explicit feedback, thereby driving the acquisition process. Usage-based theories, in contrast, view language learning as an emergent process shaped by exposure to frequent patterns in the input rather than reliance on innate grammatical rules. Tomasello's 2003 framework argues that children—and by extension, learners—construct linguistic knowledge through the accumulation of item-specific constructions derived from usage, starting with concrete, high-frequency chunks and gradually abstracting more general patterns. This approach underscores the importance of frequency, contingency, and intention-reading in social contexts, where learners generalize from specific exemplars encountered in communicative situations. A key pedagogical implication of these models is "focus on form," which integrates attention to linguistic structure within meaning-centered tasks. Developed by researchers like Long and Catherine Doughty, this method encourages learners to briefly direct attention to formal aspects of language—such as morphology or syntax—while primarily engaging in communicative activities, thereby bridging the gap between input processing and output production. Empirical support for usage-based claims in SLA comes from corpus studies revealing item-based learning patterns, where early learner productions are dominated by memorized, verb-specific constructions rather than abstract rules. For instance, analysis of Korean EFL learners' writing corpora shows that constructional development progresses from low-level, item-specific schemas (e.g., "want to + verb") to more abstract generalizations, mirroring frequency distributions in the input. Such patterns demonstrate how repeated exposure to collocations fosters incremental abstraction, aligning with interactionist principles by highlighting the role of contextual use in shaping proficiency.

Sociocultural and Complexity Theories

Sociocultural theory, rooted in the work of , posits that second-language acquisition () occurs through social mediation, where learners internalize language abilities via interactions with more knowledgeable others using cultural tools such as symbolic systems and artifacts. In this framework, mediation is central, involving processes like —where guidance from experts temporarily supports the learner—and , which serves as a self-regulatory mechanism for internalizing social dialogues into independent cognitive functions. These elements emphasize that language development is not isolated but emerges from collaborative activity within cultural contexts, influencing how learners appropriate linguistic tools for communication. A key construct in sociocultural theory is the (ZPD), defined as the difference between what a learner can achieve independently and what they can accomplish with assistance from a more capable peer or instructor. In , the ZPD facilitates progression from assisted performance, such as collaborative problem-solving in target tasks, to autonomous use, enabling learners to expand their linguistic capabilities through guided interaction. This dynamic highlights the role of social collaboration in bridging current abilities and potential development, underscoring that optimal learning occurs when support is calibrated to the learner's immediate needs. Complexity theories, particularly Dynamic Systems Theory (DST), view SLA as a nonlinear process within complex adaptive systems, where emerges from interactions among multiple variables such as input, , and , leading to variability and attractor states—stable patterns that guide development. Unlike linear models, DST accounts for the emergent, unpredictable nature of acquisition, where small changes can yield significant shifts, and development involves phases of instability before stabilizing into more proficient states. factors, such as interpersonal dynamics, contribute to these interactions by influencing the system's trajectory. Applications of DST in SLA include portfolio assessments, which track longitudinal variability in learners' output to profile developmental dynamics rather than static proficiency levels, revealing patterns of growth over time.

Outcomes and Long-Term Effects

Ultimate Attainment and Proficiency Levels

Ultimate attainment in second language acquisition () refers to the end state or plateau of that learners reach after extensive exposure and practice, varying widely from persistent interlanguage fossilization—where non-target-like features become stabilized and resistant to change—to near-native competence in grammar, vocabulary, and . Fossilization occurs when learners stabilize at an incomplete stage, often due to incomplete input or lack of , resulting in systematic errors that do not progress toward the target language . In contrast, some adult learners achieve near-native levels, particularly in syntax and , though complete native-like mastery remains rare for post-critical-period acquirers. Among linguistic domains, proves most resistant to ultimate attainment, with persistent foreign accents even in highly proficient late learners, as phonetic categories from the often interfere with new sound systems despite years of . This resistance stems from entrenched perceptual mechanisms that solidify after , making it harder to form equivalent phonetic norms for novel sounds compared to grammatical structures. Standardized proficiency models provide frameworks to assess and categorize these attainment levels. The American Council on the Teaching of Foreign Languages (ACTFL) Proficiency Guidelines outline five main levels—, , Advanced, Superior, and Distinguished—each with sublevels (Low, Mid, High) except Distinguished, evaluating communicative abilities across speaking, , reading, and writing in real-world tasks from basic survival needs at to nuanced, culturally adept at Superior. Similarly, the Common European Framework of Reference for Languages (CEFR) defines six levels (A1 to ), grouped as Basic User (A1-A2), Independent User (B1-B2), and Proficient User (C1-), focusing on practical language use for social, educational, and professional purposes, with representing near-native fluency in complex, abstract contexts. These models emphasize functional proficiency over isolated knowledge, aiding in benchmarking ultimate attainment across diverse learners. Key predictors of ultimate attainment include age of onset, the quantity and quality of input, and ongoing language use. Earlier age of onset, particularly before , correlates with higher proficiency due to greater , though late starters can still reach advanced levels with sufficient exposure. Abundant, comprehensible input from native speakers enhances convergence to target norms, while high-quality, interactive input—such as —outweighs mere quantity by providing contextual . Continued use post-acquisition sustains proficiency, preventing stagnation at lower levels. Case studies of late learners illustrate these predictors in action, particularly in speech domains. Research by James Flege on adult immigrants demonstrates that prolonged in naturalistic settings enables native speakers learning English to achieve native-like and of certain sounds, such as distinguishing /i/ and /ɪ/, through extensive high-quality input over decades, challenging strict age constraints. In Flege's studies of late bilinguals in the U.S., those with over 20 years of daily with native English speakers often attained superior phonetic proficiency, underscoring the role of experience in overriding initial age disadvantages. These findings highlight how can propel late learners toward high proficiency, though full elimination remains elusive.

Language Attrition and Retention

Language attrition refers to the gradual loss or degradation of linguistic abilities in a previously acquired , often the first (L1) or a second (L2), due to diminished exposure or use, while retention encompasses the strategies and factors that help maintain proficiency over time. This process typically follows the peak proficiency or ultimate attainment achieved during acquisition, where initial gives way to decline if input ceases. In bilingual contexts, attrition can affect both receptive skills, such as and , and productive skills, like speaking and writing, with the latter often deteriorating more rapidly due to higher demands on retrieval and output. Attrition may be temporary, as in short-term disuse leading to rusty performance that recovers with renewed practice, or permanent, involving irreversible structural changes in the linguistic system when exposure is absent for extended periods. The primary causes of language attrition include reduced frequency of use, which lowers the activation threshold for linguistic elements, and from a dominant language that competes for cognitive resources during . Michel Paradis' activation threshold model (2007) posits that items require regular activation to maintain low thresholds for retrieval; prolonged non-use raises these thresholds, making access slower and more error-prone, while recency of use and from the dominant language exacerbate the effect. For instance, immigrants immersed in a new linguistic environment often experience where L2 structures intrude on L1 production, leading to substitutions or simplifications. In bilingual attrition, particularly among immigrants, the L1 undergoes erosion as the societal becomes dominant, with , , and showing progressive decline over generations. Children of immigrants are especially vulnerable to this L1 erosion compared to adults, as their developing language systems are more plastic and susceptible to rapid shifts in input dominance, often resulting in incomplete L1 acquisition or accelerated loss if home language support is insufficient. Adults, having more entrenched L1 representations from years of use, exhibit slower and less severe attrition, primarily in less frequent lexical items rather than core . Retention strategies play a crucial role in mitigating , with programs providing structured instruction and cultural reinforcement to sustain L1 proficiency in immigrant communities. maintenance approaches, such as dual-language programs in schools, expose learners to balanced input in both languages, fostering long-term retention by integrating s into formal education and daily interactions. These interventions emphasize consistent use and positive attitudes toward the , helping to counteract erosion by lowering reactivation thresholds and reducing interference effects.

Contemporary Research and Applications

Neuroscientific Insights

Neuroimaging studies using (fMRI) and (EEG) have revealed that adult second-language acquisition (SLA) primarily recruits the left (IFG), particularly (Brodmann areas 44 and 45), for syntactic processing, similar to first-language (L1) mechanisms but with notable differences in neural engagement. In proficient adult learners, L2 syntax processing activates the left IFG, yet often requires broader recruitment of prefrontal and temporal regions compared to L1, indicating reduced neural efficiency and greater cognitive effort. EEG data further show delayed event-related potentials, such as the N400 component, in L2 semantic processing among adults, reflecting less automatic integration than in native speakers. The neurobiology of the in SLA involves developmental processes like myelination and , which diminish brain plasticity after childhood, limiting optimal L2 attainment. Myelination accelerates in language-related tracts during early years, enhancing connectivity in perisylvian regions, but plateaus post-adolescence, correlating with reduced L2 phonological and grammatical proficiency. refines neural circuits by eliminating excess connections, particularly in the and IFG, which supports efficient L1 acquisition but constrains adult for novel languages. Recent 2020s studies on gray matter density highlight this: earlier L2 onset (before age 7) is linked to higher gray matter volume in the left IFG and temporal pole, whereas later acquisition shows sparser density, underscoring age-related plasticity declines. These findings align with behavioral evidence of age effects in ultimate L2 proficiency. Bilingualism from SLA confers structural and functional advantages to the brain, particularly in executive control, as demonstrated in Ellen Bialystok's research throughout the 2010s. Lifelong bilinguals exhibit enhanced activity and denser white matter in the anterior , facilitating and task-switching during language selection. This advantage arises from constant L1-L2 competition, strengthening the for , with bilingual children outperforming monolinguals on flanker tasks by ages 4-5. Such enhancements persist into adulthood, delaying age-related cognitive decline by up to 4-5 years. Advancements in 2024-2025 research employ in animal models, such as songbirds, to simulate human-like input suspension effects on vocal acquisition and probe boundaries. In adult zebra finches, optogenetic disinhibition of parvalbumin in the premotor nucleus HVC reopens , enabling novel syllable learning akin to juvenile stages, even after sensory input windows close. These manipulations mimic input suspension by suppressing inhibitory circuits that normally gate auditory-motor integration post-, revealing molecular parallels to human barriers, including pathway modulation. Such findings suggest targeted neural interventions could extend for late L2 learning in humans.

Technology and AI in SLA

Artificial intelligence () and digital technologies have revolutionized second-language acquisition () by providing personalized, interactive, and immersive learning experiences that adapt to individual learner needs. Adaptive platforms leverage (NLP) and to deliver tailored content, while (VR) simulations offer environments for practicing communicative skills in context. These tools bridge gaps between theoretical and practical teaching, enhancing engagement and outcomes in SLA. AI tutors, such as , employ systems and for immediate feedback, optimizing retention and correction of errors in real-time. In , Duolingo introduced AI-powered features like Video Call, which simulates conversations with virtual characters using generative AI for dynamic interactions, and , which present real-life scenarios to build practical language use. These enhancements have improved learner proficiency by providing personalized corrections and reinforcement, with studies showing increased motivation and accuracy in speaking tasks among users. Generative AI chatbots further support by offering contextual practice and automated assessments, outperforming traditional methods in fostering fluency. Virtual reality immersion enables naturalistic practice, particularly in developing , by simulating cultural and social contexts akin to study abroad experiences. High-immersion VR environments allow learners to engage in interactions with avatars, enhancing sensitivity to nonverbal cues and strategies in the target . A 2025 study demonstrated that VR exposure significantly boosts communicative confidence and perceived fluency in foreign language learners, with participants showing measurable gains in pragmatic after repeated simulations. These tools provide scalable alternatives to physical , especially for diverse learners facing access barriers. Machine learning models apply to forecast learner trajectories, identifying at-risk patterns and recommending interventions to align insights with classroom applications. In contexts, algorithms analyze interaction data to predict proficiency plateaus, enabling adaptive curricula that personalize pacing and content. A 2025 comparative analysis of models for EFL students found that ensemble methods, such as random forests, achieved over 85% accuracy in predicting language performance based on behavioral logs from smart learning environments. This approach bridges empirical with teaching by quantifying progress and mitigating dropout risks. Despite these advances, challenges persist, including that disadvantages learners from diverse first-language (L1) backgrounds. AI systems trained on predominantly English-centric datasets often perpetuate cultural stereotypes and underrepresent non-Western L1s, leading to inequitable feedback and reduced effectiveness for multilingual users. A 2025 analysis revealed that such biases in language learning tools exacerbate exclusion in diverse educational settings, with error rates varying significantly by L1, highest for speakers of low-resource languages. Addressing this requires inclusive data curation and bias-auditing protocols to ensure equitable support.

Future Directions and Challenges

Research in second-language acquisition (SLA) has historically focused on high-resource languages such as English, , and , leaving significant gaps in understanding acquisition processes for low-resource languages spoken by fewer than a million people globally. These languages, often oral and undocumented, pose unique challenges due to limited pedagogical materials and data for computational models, hindering equitable SLA support in diverse linguistic ecologies. Similarly, indigenous SLA contexts remain understudied, with barriers including cultural disconnection from dominant systems and historical language suppression, which exacerbate loss and impede revitalization efforts. For instance, indigenous learners frequently face low readiness in second languages due to inadequate bridging from , underscoring the need for context-specific interventions. Addressing these gaps requires expanded empirical studies on typological diversity and community-led research to inform inclusive policies. The has accelerated shifts toward learning models in , blending remote and in-person input, but recent studies highlight ongoing challenges to in these environments. A 2025 investigation of English as a (EFL) learners found that models boosted self-determined compared to fully synchronous or asynchronous formats, yet persistent issues like digital fatigue and unequal access to diminished engagement for some. Post-pandemic analyses from 2024 emphasize that remote input's variability affects extrinsic , particularly in non-English-major contexts, where learners report lower persistence without structured social interaction. Future directions must prioritize adaptive frameworks that sustain motivational trajectories through personalized feedback and community-building tools. Inclusivity in SLA demands greater attention to neurodiversity, such as , which complicates phonological processing and orthographic mapping in second languages, often leading to heightened anxiety and slower proficiency gains. shows that dyslexic adults acquiring English as a foreign language exhibit persistent deficits in and oral fluency, necessitating tailored strategies like multisensory instruction to bridge these challenges. Bilingual approaches can mitigate such difficulties by leveraging first-language strengths, yet neurodiverse learners remain underrepresented in SLA studies. Complementing this, equity in global access requires dismantling barriers for multilingual populations, where 40% worldwide lack education in familiar languages, disproportionately affecting low-income regions. A 2025 report advocates for multilingual policies to enhance , emphasizing for and groups to prevent proficiency disparities. Interdisciplinary integration offers promising avenues for SLA advancement, including AI ethics to ensure unbiased tools that respect learner privacy and cultural nuances in automated feedback systems. Ethical frameworks must address risks like data exploitation in AI-driven apps, promoting transparent algorithms for equitable language pedagogy. Climate-induced migration is reshaping multilingualism, compelling SLA research to examine how displaced populations acquire host languages amid trauma and identity shifts, with studies noting increased linguistic diversity in classrooms as a global norm. Additionally, longitudinal big data approaches enable tracking of acquisition trajectories over time, revealing patterns in syntactic complexity and motivation that traditional methods overlook, though ethical data handling remains a priority. Building on neuroscientific and technological foundations, these efforts call for collaborative, cross-field initiatives to tackle SLA's evolving complexities.

References

  1. [1]
    Second Language Acquisition - an overview | ScienceDirect Topics
    'Second language acquisition' in a broad sense refers to the learning of a nonnative language after the first language (L1) (ie, the native language) has been ...
  2. [2]
    [PDF] Second Language Acquisition: A Framework and Historical ... - ERIC
    Jul 31, 2020 · Second Language Acquisition (SLA) is one main branch of Applied Linguistics, which is well-known by the research and practices in other ...
  3. [3]
    (PDF) Second Language Acquisition: An Overview and Theoretical ...
    Jan 30, 2023 · This paper discusses the most important theoretical background and the relevant literature on the acquisition of second language.
  4. [4]
    [PDF] Second Language Acquisition: A General Overview - AIIAS Journals
    Apr 1, 2016 · Generally, SLA is defined as both the study of people who are learning an additional language after they know how to speak their first; and the ...
  5. [5]
    [PDF] Second Language Acquisition in Adults: From Research to Practice
    Second language acquisition (SLA) is the study of how second languages are learned and the factors that influence the process. SLA researchers examine how ...
  6. [6]
    Larry Selinker | U-M LSA Linguistics
    Larry Selinker helped found the field of Second Language Acquisition, suggesting early on (Selinker, 1972), the robust concepts of “interlanguage” and ...
  7. [7]
    https://doi.org/10.1515/iral.1972.10.1-4.209
  8. [8]
    [PDF] Diverse Conceptualizations of “Competence” in Second Language ...
    Jul 18, 2023 · This article traces the intellectual roots and developments of the notion of competence in second language (L2) teaching and research.
  9. [9]
    [PDF] Principles and Practice Second Language Acquisition
    Krashen, S. (1989) We acquire vocabulary and spelling by reading: Additional evidence for the input hypothesis. Modern Language Journal 73, 440-464.
  10. [10]
    [PDF] What Are the Origins of Second Language Acquisition as a ...
    on L2 acquisition was Larry Selinker's 1972 essay, “Interlanguage.” In an ambi- tious attempt to connect many ideas, Selinker argued a number of points.
  11. [11]
    On the Distinction between Second-Language Acquisition and ...
    Second-language acquisition involves natural communication in the learner's environment, while foreign-language learning does not, with little natural ...
  12. [12]
    Second language acquisition and acculturation: similarities and ...
    Jul 12, 2023 · The present study examined similarities and differences between immigrant and refugee newcomers on L2 vocabulary and literacy as well as acculturation.Abstract · Introduction · Results · Discussion
  13. [13]
    [PDF] Second Language Acquisition Research and Applied Linguistics
    Also found in this domain is work on foreign language acquisition. Often referred to as foreign language learning, it is distinguished by a lack of access ...
  14. [14]
    (PDF) Second and Additional Language Acquisition - ResearchGate
    Provides a comprehensive introduction to this interdisciplinary field of research and practice, dealing with practical issues of language and communication.<|control11|><|separator|>
  15. [15]
    Interacting in Japanese and English in the English as a Foreign ...
    This study explored the attitudes of Japanese high school students toward the use of English in language classes to better determine when and how teachers may ...
  16. [16]
    Linguistics across cultures : Robert Lado - Internet Archive
    Jul 24, 2023 · Linguistics across cultures. by: Robert Lado. Publication date: 1957. Collection: internetarchivebooks; inlibrary; printdisabled. Contributor ...
  17. [17]
    [PDF] ED019903.pdf - ERIC
    V/4, NOVEMBER 1967. Within this new context the study of errors takes on a new importance and ... learn it. S. P. Corder. Department of Applied Linguistics.Missing: original | Show results with:original
  18. [18]
    Pidgin and Creole Linguistics - Project MUSE
    If the situation of the pidgin speaker is one of handicapped second- language learning, then that of the first-generation creole speaker is surely one of ...
  19. [19]
    (PDF) Universal Grammar and Second Language Acquisition
    This entry will introduce universal grammar (UG) with respect to second language (L2) acquisition. It will first deal with the notion of UG and how it works.
  20. [20]
    Universal Grammar and Second Language Acquisition
    This book explores the relationship between linguistic universals and second language acquisition. Although no knowledge of generative grammar is presupposed.
  21. [21]
    [PDF] UNIVERSAL GRAMMAR IN SECOND LANGUAGE ACQUISITION:
    In this paper, I provide an overview of differing perspectives on the role of. Universal Grammar (UG) in second language acquisition (SLA). I will suggest that ...Missing: seminal | Show results with:seminal
  22. [22]
    (PDF) Natural Sequence in Child Second Language Acquisition
    Aug 6, 2025 · PDF | The acquisition sequences of 11 English functors were compared for native Chinese- and Spanish-speaking children learning English.
  23. [23]
    [PDF] Comparing and Contrasting First and Second Language Acquisition
    The Interlanguage Theory plays a crucial role in arriving at findings on how L2 learners move from their mother tongue towards the target language.
  24. [24]
    Biological foundations of language : Lenneberg, Eric H
    Feb 28, 2020 · 489 pages : 24 cm. The study of language is pertinent to many fields of inquiry. It is relevant to psychology, anthropology, philosophy, and medicine.
  25. [25]
    Age and learning environment: Are children implicit second ...
    Feb 26, 2016 · Children learn second languages implicitly, but explicit instruction can increase their awareness of grammatical rules, similar to adults. ...
  26. [26]
    Are children implicit second language learners? - PubMed
    Feb 26, 2016 · Children are thought to learn second languages (L2s) using primarily implicit mechanisms, in contrast to adults, who primarily rely on ...
  27. [27]
    Plasticity of the language system in children and adults - PMC
    The neural plasticity involved in tuning phonological representations for multiple native languages is not well understood (see Höhle et al., 2020 for a recent ...
  28. [28]
    Converging Evidence for Differential Specialization and Plasticity of ...
    Dec 9, 2020 · A multipronged analytic approach revealed converging evidence for striking differences in hemispheric specialization and plasticity among the language systems.Mri Data Analysis · Results · Lateralization In...<|separator|>
  29. [29]
    AGE OF ONSET AND NATIVELIKE L2 ULTIMATE ATTAINMENT OF ...
    May 14, 2012 · Research has consistently shown there is a negative correlation between age of onset (AO) of acquisition and ultimate attainment (UA) of either pronunciation ...
  30. [30]
    [PDF] The Natural Approach. Language Acquisition in the Classroom
    Implications of Second Language Acquisition Theory. The Natural Approach ... We acquire language when we obtain comprehensible input, when we understand what we ...
  31. [31]
    Overgeneralization - Multilingual Pedagogy and World Englishes
    Overgeneralization means that whenever learners encounter a new rule or pattern in the target language, they assume the rule or pattern operates without ...
  32. [32]
    [PDF] Interlanguage and the Models Before - ERIC
    Sep 16, 2018 · It is defined by its coiner, Larry Selinker. (1972), who in his article Interlanguage, views this term as “a separate linguistic system based on ...
  33. [33]
    [PDF] U-shaped Trajectories in an L2 context - Revistas Universidad de Vigo
    U-shaped trajectories in language learning and second language acquisition, while also presenting theoretical models to account for the learning curve.
  34. [34]
    [PDF] Social Context and Interlanguage Variability - DigitalCommons@COD
    Apr 9, 2025 · Selinker's foundational work emphasized that learners do not merely mimic the target language (L2) but create a unique system influenced by ...
  35. [35]
    When-questions in second language acquisition - ResearchGate
    Aug 10, 2025 · This paper is a first report on a longitudinal study of the acquisition of a syntactic rule: the inversion of WH-questions.1 The general aim ...
  36. [36]
    https://dc.cod.edu/cgi/viewcontent.cgi?article=1002&context=languages_fac_staff
  37. [37]
    31 - The Acquisition of Second Language Spanish Morphosyntax
    This chapter provides an overview of relevant research on the acquisition of Spanish morphosyntax in the context of second language (L2) acquisition (SLA).
  38. [38]
    Psychological Constraints on the Teachability of Languages*
    Nov 7, 2008 · This paper reports on the influence of formal instruction on L2 acquisition in an instructional experiment with child learners.<|control11|><|separator|>
  39. [39]
    [PDF] Further Evidence for the Developmental Stages of Language ... - ERIC
    As predicted by Pienemann's Teachability Hypothesis (1992), only the learners who had met the prerequisites for instruction could acquire the grammatical points ...
  40. [40]
    (PDF) Selinker-Interlanguage - Academia.edu
    Selinker coined the term 'interlanguage' in 1972, highlighting the systematic nature of learner language and its relationship to both first and target ...
  41. [41]
    [PDF] Implication of IL Fossilization in Second Language Acquisition - ERIC
    Selinker first put forwarded the notion of fossilization in the paper Interlanuage in 1972. He noted that 95% of L2 learners failed to reach the same level of ...
  42. [42]
    Fossilization in second language acquisition - English Coach Online
    Jan 8, 2021 · I also discuss methods which I believe might help learners to overcome fossilization. ABBREVIATIONS: L1 - first language. L2 - second language.<|control11|><|separator|>
  43. [43]
    [PDF] A Study of Interlanguage Fossilization in Second Language ...
    In the process of second language acquisition, learners tend to be interfered by their mother tongue, thus producing errors. Those interferences are mainly ...
  44. [44]
    Causes of Interlanguage Fossilization and the Coping Strategies
    Generally, the internal causes include age, motivation, mother. language ... When learning a second language, fossilization due to improper learning strategies is ...
  45. [45]
    [PDF] The Social Factors of Fossilization - SIT Digital Collections
    Apr 23, 2018 · First, social environment will influence the input and feedback received by learners; second, learners employ different aspects of their ...Missing: insufficient | Show results with:insufficient
  46. [46]
    [PDF] Fossilization in Adult Second Language Acquisition
    The longitudinal study (Han, 1998) I performed then not only convinced me of the reality of fossilization, but kindled in me an even greater interest in seeking ...
  47. [47]
    [PDF] 16 Stabilization and Fossilization in Interlanguage Development
    Third, Selinker repeatedly asserts that fossilization, resulting in non-target- like ultimate attainment, operates in learners regardless of age; for example, ...
  48. [48]
    Contrastive Analysis Hypothesis and Second Language Learning
    Aug 8, 2025 · This article aims to provide an overview of some of the issues related to contrastive analysis hypothesis in second language learning.
  49. [49]
    (PDF) Language transfer: interlingual errors in Spanish students of ...
    Aug 5, 2025 · This paper aims at finding out the most common types of interlingual errors that Spanish students make when they are learning English as a foreign language.
  50. [50]
    Training Japanese listeners to identify English /r/ and /l/: A first report
    Native speakers of Japanese learning English generally have difficulty differentiating the phonemes /r/ and /l/, even after years of experience with English.
  51. [51]
    Code-Switching at the Interfaces - MDPI
    Jul 25, 2024 · Interface phenomena involve the interaction of different linguistic domains (e.g., syntax, morphology, phonology, pragmatics). Studies on code- ...
  52. [52]
    First-language influence on second language speech perception ...
    We conclude that bilinguals are cross-linguistically influenced by L1 phonotactic constraints during L2 processing when metalinguistic demands are higher.
  53. [53]
    First Language Attrition: What It Is, What It Isn't, and What It Can Be
    This review aims at clarifying the concept of first language attrition by tracing its limits, identifying its phenomenological and contextual constraints.
  54. [54]
    BIDIRECTIONAL CROSSLINGUISTIC INFLUENCE IN L1-L2 ...
    Apr 17, 2008 · This study investigates the possibility of a bidirectional relationship. We examine the domain of manner of motion, in which monolingual Japanese and English ...
  55. [55]
    Cross-linguistic Similarity in Foreign Language Learning
    In terms of psychotypology (Ringbom, 2007) , French and Spanish are perceived as typologically similar by both groups (on average 70 % of the L4 Spanish ...
  56. [56]
    Language Aptitude and Crosslinguistic Influence in Initial L2 Learning
    Nov 18, 2020 · This article aims at exploring contributions of both language learning aptitude and L1 background to successful L2 achievement.
  57. [57]
    Markedness and Second Language Acquisition
    This paper discusses markedness definitions and how prior language experience may lead to transfer of marked structures in second language acquisition.
  58. [58]
    MARKEDNESS AND SECOND LANGUAGE ACQUISITION - jstor
    In this paper, I shall adopt a formal definition of markedness that is used in work on language learnability within the framework of generative grammar, an ...
  59. [59]
    MARKEDNESS IN SECOND LANGUAGE ACQUISITION<link href ...
    Markedness, in second language acquisition, is related to complexity, where more complex expressions are more marked, and can be linked to the relationship of  ...
  60. [60]
    Salience in Second Language Acquisition: Physical Form, Learner ...
    Aug 29, 2016 · (1) When presented with competing cues to interpretation, learners are more likely to attend to physically more salient cues in the input. (2) ...Missing: saliency | Show results with:saliency
  61. [61]
    [PDF] SALIENCE IN USAGE- BASED SLA - University of Michigan
    May 31, 2017 · Salient items or features are attended, are more likely to be perceived, and are more likely to enter into subsequent cognitive processing and.
  62. [62]
    FSI language difficulty
    What are the FSI rankings? · Category I – Languages that usually require around 24-30 weeks or 600-750 class hours to reach S-3/R-3 proficiency. · Category IV – ...
  63. [63]
    Foreign Service Institute Language Difficulty Rankings | Atlas & Boots
    Sep 21, 2021 · Category I: 23-24 weeks (575-600 hours) Languages closely related to English · Category II: 30 weeks (750 hours) Languages similar to English.
  64. [64]
    Language Difficulty Ranking
    The Foreign Service Institute (FSI) has created a list to show the approximate time you need to learn a specific language as an English speaker.
  65. [65]
    [PDF] Working memory and second language development - ERIC
    Aptitude theory: WM has long been theorized to play a key role in foreign language aptitude, whether it is regarded as central to it (Miyake & Friedman, 1998) ...
  66. [66]
    WORKING MEMORY CAPACITY AND L2 READING
    Aug 2, 2021 · The relationship between working memory (WM) and second-language (L2) reading has been extensively examined, with mixed results.
  67. [67]
    The role of WM in second language reading comprehension
    Working memory (WM) has been identified as a likely central component of language learning aptitude (Carroll, 1981, Miyake and Friedman, 1998, Skehan, 1989).
  68. [68]
    [PDF] Learning Strategies in Second Language Acquisition
    Research in metacognitive and cognitive learning strategies suggests that transfer of strategy training to new tasks can be maximized by pairing metacognitive ...
  69. [69]
    (PDF) Metacognition and Self-Regulated Learning (SRL) in Second ...
    Studies show that incorporating self-regulated learning (SRL) strategies into foreign language teaching encourages the development of autonomous learners.
  70. [70]
    [PDF] Language Learning Strategies: Is There a Best Way To Teach - ERIC
    O'Malley, J.M., Chamot, A.U. & Kupper, L. (1995). Listening comprehension strategies in second language acquisition. In H.D. Brown & S. T. Gonzo (Eds.), ...
  71. [71]
    [PDF] Pedagogies Proving Krashen's Theory of Affective Filter - ERIC
    Krashen's (1982) hypothesis of second language achievement consists of five major key points, which are Acquisition-Learning hypothesis, the Monitor hypothesis, ...
  72. [72]
    The Role of Consciousness in Second Language Learning 1
    I conclude that subliminal language learning is impossible, and that noticing is the necessary and sufficient condition for converting input to intake.
  73. [73]
    [PDF] Speech-accommodation theories: a discussion in - terms of second ...
    In an attempt to rectify such omissions while at the same time integrating constructs from the previ- ous models, Giles and Byrne (1982) presented the core ...
  74. [74]
    Linguistic imperialism : Phillipson, Robert - Internet Archive
    May 13, 2023 · 1992. Topics: English language -- Political aspects -- Developing countries, English language -- Study and teaching -- Foreign speakers ...
  75. [75]
    https://archive.org/details/linguisticimperi0000phil
  76. [76]
    Age and Second Language Acquisition and Processing: A Selective ...
    Jul 26, 2006 · This article provides a selective overview of theoretical issues and empirical findings relating to the question of age and second language acquisition (L2A).Missing: vocabulary | Show results with:vocabulary
  77. [77]
    Foreign language aptitude theory: Yesterday, today and tomorrow
    Dec 21, 2016 · Other aptitude factors in Carroll's original model (Reference Carroll and Glaser1962, Reference Carroll and Diller1981), such as phonetic coding ...
  78. [78]
    (PDF) Use of the Modern Language Aptitude Test - ResearchGate
    Key abilities assessed by the. MLAT. •Phonetic coding ability. •Grammatical sensitivity. •Rote memory. •Inductive language learning ability ... John B Carroll.
  79. [79]
    [PDF] Motivation in Second Language Acquisition: A State of the Art Article
    Gardner's (1985) conceptualization of the integrative motivation is that it includes orientation (i.e. a class of reasons for learning a second language), ...
  80. [80]
    An Instrumental Motivation In Language Study
    The major purpose of this study was to investigate the effects of integrative motivation and instrumental motivation on the learning of French/English ...
  81. [81]
    [PDF] Self-efficacy in Second/Foreign Language Learning Contexts - ERIC
    Sep 12, 2012 · Abstract. This study reviews the empirical literature of self-efficacy, a central component of social cognitive theory, in the.
  82. [82]
    Self-efficacy in second language acquisition - ResearchGate
    According to Bandura (1997), self-efficacy plays a crucial role in shaping learners' persistence, effort, and achievement, as individuals with higher self- ...
  83. [83]
    How specific is second language-learning ability? A twin study ...
    Sep 22, 2015 · A Dutch study using over 1600 12 to 26-year-old twin pairs, reported a high heritability estimate (71%). However, this study used self-reported ...
  84. [84]
    (PDF) Two by Two: A Twin Study of Second-Language Acquisition
    Aug 9, 2025 · In this report, we provide initial results of the first application of the classic twin design to second-language acquisition.
  85. [85]
    Multilingualism and Metalinguistic Awareness - Wiley Online Library
    Jun 21, 2019 · Metalinguistic awareness is an aspect of metacognition that results from looking at language as a system beyond its meanings.
  86. [86]
    [PDF] The Role of Metalinguistic Awareness in Multilingual Acquisition
    Multilingual acquisition is a nonlinear and complex dynamic process. The past several decades of research have revealed that a number of factors interact ...
  87. [87]
    Integrated, Not Isolated: Defining Typological Proximity in ... - Frontiers
    Moreover, typological relatedness in the synchronic sense plays an important role in understanding phenomena associated with bilingualism, including second ...Introduction · Holistic View - Integrated... · Dynamic Integration · Testing Our Model
  88. [88]
    (PDF) Transfer and Typological Proximity in the Context of Second ...
    Aug 10, 2025 · In this article, the issue of cross-linguistic influence in second language acquisition is examined from a processing perspective.
  89. [89]
    The additive effect of bilingualism on third language acquisition
    This article looks at the general effects of bilingualism on cognitive development and highlights the specific effects of bilingualism on third language ...
  90. [90]
    The influence of bilingualism on third language acquisition: Focus ...
    Jun 15, 2011 · This paper focuses on the advantages that bilinguals have over monolinguals when acquiring an additional language.
  91. [91]
    Code-switching experience as a mitigating factor for cross-linguistic ...
    Greater code-switching experience limits phonetic interference, and code-switching experience serves to mitigate short-term cross-linguistic interference.
  92. [92]
    Language Distance Moderates the Effect of a Mixed-Language ... - NIH
    Apr 23, 2024 · This study aims to explore the impact of language mixing on vocabulary acquisition in bilingual children and whether language distance moderates this impact.
  93. [93]
    Guiding Principles for Language Learning - ACTFL
    These Guiding Principles for Language Learning identify what is effective in language learning and guide educators and learners.Benefits of Language Learning · Design Communicative Tasks · Opening Statement<|separator|>
  94. [94]
    (PDF) The Role of Four Skills in Teaching and Learning
    Aug 7, 2025 · This study examines the critical role of the four fundamental language skills—listening, speaking, reading, and writing—in second language ...
  95. [95]
    [PDF] Nation And Macalister Language Curriculum Design
    The curriculum encourages equal attention to all four language skills: - Listening and ... (listening, speaking, reading, writing), fluency building, and the ...
  96. [96]
    Optimal timing of treatment for errors in second language learning
    Only three studies concluded that delayed CF was more effective than immediate feedback, but they share limitations due to internal validity issues (Rahimi and ...
  97. [97]
    Immediate vs Delayed Correction Feedback (CF) and Accuracy of ...
    Aug 6, 2025 · Students that receive immediate feedback have higher levels of anxiety than students that receive delayed feedback during speaking activities ( ...
  98. [98]
    (PDF) Interaction or collaboration? Group dynamics in the foreign ...
    Jul 3, 2025 · This chapter reports on a classroom-based quasi-experimental study examining the relationship between interactional moves and collaborative patterns in peer ...
  99. [99]
    Enhancing Young Learners' Peer Collaboration: Pedagogical Ideas ...
    Jul 14, 2024 · The term peer collaboration describes a pair/small group working together on all parts of the task where learners help each other, engage with ...<|separator|>
  100. [100]
    Common European Framework of Reference for Languages (CEFR)
    It presents the key aspects of the CEFR for teaching and learning in a user-friendly form and contains the complete set of extended CEFR descriptors, replacing ...CEFR and its language versions · CEFR Descriptors · The CEFR Levels · Navigation
  101. [101]
    [PDF] Assigning CEFR Ratings to ACTFL Assessments
    There are two major frameworks for learning, teaching, and assessing foreign language skills: the U.S. defined scales of proficiency, i.e., the ACTFL ...
  102. [102]
    [PDF] Contexts of Acquisition: Effects of Formal Instruction and Naturalistic ...
    In. Krashen's theory, second language acquisition (SLA) comes naturally as a result of implicit processes occurring while the learner is receiving ...
  103. [103]
    Are Classroom and Naturalistic Acquisition the Same?
    The results of this study support the claim that the classroom and naturalistic L2 acquisition of complex grammatical features such as word order follow similar ...
  104. [104]
    [PDF] Language and Content Outcomes of CLIL and EMI - ERIC
    CBI may be practiced in various forms, with the most common being Content and Language In- tegrated Learning (CLIL) or English-Medium Instruction (EMI) (Brinton.
  105. [105]
    TASK-BASED LANGUAGE LEARNING AND TEACHING
    Sep 1, 2004 · This book includes 10 chapters, each focusing on tasks and their rationale, design, and implementation. In chapter 1, definitions and features ...
  106. [106]
    Task-Based Language Teaching: A Systematic Review of Research ...
    This systematic review aims to evaluate the research and applications of TBLT, analyzing its impact on language proficiency, student engagement, and ...
  107. [107]
    [PDF] A Systematic Review of Task-Based Language Teaching for EFL ...
    Jun 12, 2024 · Thirty-eight articles were reviewed in the present study aiming to understand the effect of TBLT on English speaking proficiency in the EFL ...
  108. [108]
    The Effects of Spaced Practice on Second Language Learning: A ...
    Feb 6, 2022 · This meta-analysis investigates earlier studies of spaced practice in second language learning. We retrieved 98 effect sizes from 48 experiments ...
  109. [109]
    Effects of Flipped Learning on Language Learning Outcomes
    Apr 29, 2025 · This meta-analysis assesses flipped learning's impact on language learning outcomes vis-à-vis non-flipped instruction, encompassing distinct moderators.
  110. [110]
    [PDF] THE AUDIOLINGUAL METHOD BY - ERIC
    Since Audiolingualism was theoretically based on the dominant linguistic and learning theory of the time, it demanded a complete reorientation of the foreign.
  111. [111]
    (PDF) A review study of contrastive analysis theory - ResearchGate
    Jan 29, 2017 · This research paper aims at reviewing one of the most influential theories of second language acquisition, which is Contrastive Analysis theory.
  112. [112]
    [PDF] Verbal Behavior - B. F. Skinner Foundation
    The book has two major components: a systematic analysis of the language behavior of the individual speaker in terms of reinforcement, extinction, punishment,.
  113. [113]
    Verbal behavior by B.F. Skinner: Contributions to analyzing early ...
    BF Skinner's Verbal Behavior (1957) is analyzed in the context of early language learning. In the book, Skinner did not emp hasize the foundations for language ...Missing: second | Show results with:second
  114. [114]
    The background, history and progress of Audio-lingual Method
    The Audio-Lingual method of teaching English language as a second or target language had begun its journey during World War II, flourishing as the Army method.Missing: acquisition | Show results with:acquisition
  115. [115]
    The Audio-Lingual Method: History, Key Principles, Activities
    Nov 24, 2023 · The audio-lingual method was initially created as the improved version of the direct method. It was supposed to pay much more attention to ...
  116. [116]
    Re‐reading Robert Lado, 1957, Linguistics across Cultures. Applied ...
    Jul 23, 2007 · It is customary in applied linguistics to attribute the refutation of the contrastive analysis hypothesis to its association with behaviorism ...
  117. [117]
    Re‐reading Robert Lado, 1957, Linguistics across Cultures. Applied ...
    Aug 9, 2025 · Many assumptions behind Lado's theory, which laid the foundations for the Contrastive Analysis Hypothesis, are no longer valid however. Most ...
  118. [118]
    [PDF] An Overview of Contrastive Analysis Hypothesis - DergiPark
    May 5, 2015 · Negative transfer occurs when previous performance disrupts the performance of a second task. The latter can be referred to as interference, in ...<|control11|><|separator|>
  119. [119]
    Lectures on government and binding : Chomsky, Noam
    Mar 30, 2022 · Lectures on government and binding. by: Chomsky, Noam. Publication date: 1981. Topics: Generative grammar, Government-binding theory ( ...
  120. [120]
    Second Language Acquisition and Universal Grammar
    This authoritative 2003 textbook provides an overview and analysis of current second language acquisition research conducted within the generative ...
  121. [121]
    [PDF] 1 Revisiting Universal Grammar1 Jürgen M. Meisel University of ...
    Nov 6, 1998 · The theory of Universal Grammar (UG), especially in its Principles and Parameters (PPT) version, has exerted a very significant influence on ...Missing: 1990s | Show results with:1990s
  122. [122]
    [PDF] Second Language Acquisition: From Initial to Final State 131
    Full Transfer/Full Access predicts that grammars of L1 and L2 learners will differ, prior to any parameter resetting, as will the grammars of learners of ...
  123. [123]
    Constructing a Language - Harvard University Press
    Mar 31, 2005 · In this groundbreaking book, Michael Tomasello presents a comprehensive usage-based theory of language acquisition.
  124. [124]
    [PDF] A Usage-Based Study of L2 Constructional Development - ERIC
    By adopting a usage-based approach to language acquisition, this study investigated the emergence and development of L2 constructional knowledge. A total of 19 ...
  125. [125]
    (PDF) Sociocultural Theory and Second Language Acquisition
    Aug 6, 2025 · This article considers the implications of two central constructs of sociocultural theory (SCT) for second language (L2) development: mediation and ...
  126. [126]
    Sociocultural Theory and Second Language Acquisition
    This research has focused on three general areas: activity theory and the relevance of motives and goals for L2 learning; the role of private speech in L2 ...
  127. [127]
    A Dynamic Systems Theory approach to second language acquisition
    Mar 2, 2007 · In this article it is argued that language can be seen as a dynamic system, ie a set of variables that interact over time, and that language development can be ...
  128. [128]
    Introduction: Second language development as a dynamic process.
    In this contribution, some of the basic characteristics of complex adaptive systems, collectively labeled Dynamic Systems Theory (DST), are discussed.
  129. [129]
    (PDF) Second Language Developmental Dynamics - ResearchGate
    Sep 5, 2015 · Dynamic systems theory (DST) is presented in this article as a suitable approach to research the acquisition of second language (L2) because ...
  130. [130]
    Ultimate Attainment in Second Language Acquisition - ResearchGate
    Aug 7, 2025 · The older the language learner is, the less likely it is that they acquire native-like proficiency, including a native-like accent (e.g., ...
  131. [131]
    Ultimate attainment in second language acquisition | Semantic Scholar
    Dec 1, 1992 · On the prevailing view of ultimate attainment in second language acquisition, native competence cannot be achieved by postpubertal learners.Missing: range fossilized resistant
  132. [132]
    Reconceptualizing fossilization in second language acquisition - jstor
    The term 'fossilization', introduced by Selinker (1972), captures the observation that most adult second language learners never reach native-like ...<|control11|><|separator|>
  133. [133]
    Second Language Acquisition and Ultimate Attainment | Request PDF
    The notion of L2 ultimate attainment refers to the end state that one can eventually achieve in L2 acquisition, regardless of whether the L2 becomes convergent ...
  134. [134]
    NCSSFL-ACTFL Can-Do Statements
    The Can-Do Statements reflect the continuum of growth in communication skills through the Novice, Intermediate, Advanced, Superior, and Distinguished levels.
  135. [135]
    Self-assessment grid - Table 2 (CEFR 3.3) : Common Reference levels
    The self-assessment grid illustrates the levels of proficiency described in the Common European Framework of Reference for Languages (CEFR).
  136. [136]
    A critical review of age-related research on L2 ultimate attainment
    Dec 3, 2010 · In the case of extended immersion experiences, living with native speakers is a strong predictor of long-term attainment over and above age of ...
  137. [137]
    Education and Input as Predictors of Second Language Attainment ...
    This study examines the effects of education and input as predictors of adult second language acquisition in naturalistic contexts. L1 Albanian learners of ...Missing: onset | Show results with:onset
  138. [138]
    Age effects in second language acquisition - ScienceDirect.com
    A maturationally-based sensitive period has long been the favorite explanation for why ultimate foreign language attainment declines with age-of-acquisition.Missing: phonology | Show results with:phonology
  139. [139]
    the effect of experience on adults' acquisition of a second language
    THE EFFECT OF EXPERIENCE ON ADULTS' ACQUISITION OF A SECOND LANGUAGE · J. Flege, Serena Liu · Published in Studies in Second Language… 1 December 2001 ...
  140. [140]
    (PDF) Language Attrition - ResearchGate
    PDF | 'Language attrition' describes the loss of, or changes to, grammatical and other features of a language as a result of declining use by speakers.
  141. [141]
    Bridging the Gap Between Second Language Acquisition Research ...
    Nov 13, 2019 · It furthermore appears that productive skills deteriorate faster than receptive skills (e.g., Bahrick, 1984; De Groot and Keijzer, 2000), and ...
  142. [142]
    [PDF] Heritage Languages and Their Speakers - Harvard DASH
    Thus, attrition is “the temporary or permanent loss of language ability as reflected in a speaker's performance or in his or her inability to make ...
  143. [143]
    First Language Lexical Attrition in a First Language Setting - NIH
    Mar 6, 2024 · Long-term absence of activation triggers language attrition (Paradis, 2007). Non-use of the L1 lexicon means that its activation threshold ...
  144. [144]
    L1 attrition features predicted by a neurolinguistic theory of ...
    Aug 8, 2007 · The constructs from A Neurolinguistic Theory of Bilingualism (Paradis 2004) that have implications for attrition are outlined and ...
  145. [145]
    Electrophysiological evidence for cross-language interference in ...
    May 14, 2021 · Foreign language attrition (FLA) appears to be driven by interference from other, more recently-used languages (Mickan et al., 2020).Missing: dominant | Show results with:dominant
  146. [146]
    [PDF] Native Language Attrition Among Immigrants
    This study is about language erosion among immigrant children in the United States. Having worked with adult language learners at Project English and Giving ...
  147. [147]
    https://red.mnstate.edu/cgi/viewcontent.cgi?article=1759&context=thesis
  148. [148]
    Lexical attrition in younger and older bilingual adults - PMC - NIH
    Older individuals who use more than one language are vulnerable to two possible concomitant processes: L1 changes due to ageing and L1 attrition due to L2 use.
  149. [149]
    [PDF] The Importance of Maintaining a Heritage Language while Acquiring ...
    The aim of this essay is to give an overview of the topic of heritage language maintenance by looking at a body of research that covers many years of study and ...
  150. [150]
    Can Dual-Language Immersion Programs Help Maintain Immigrant ...
    Mar 26, 2024 · Students enter the program in their early years and develop reading, writing, listening, and speaking skills in a second language over time.
  151. [151]
    Beyond the home: rethinking heritage language maintenance as a ...
    May 16, 2025 · Heritage language maintenance (HLM) is an important aspect of preserving cultural identity, fostering intergenerational communication, and ...
  152. [152]
    Multilingualism and fMRI: Longitudinal Study of Second Language ...
    May 28, 2013 · (3) What is the relevance of critical periods for language acquisition and language learning? Definitions of critical periods necessarily ...
  153. [153]
    Causal evidence for the involvement of Broca's area in second ...
    Dec 20, 2022 · A wealth of correlational evidence suggests that Broca's area (the left inferior frontal gyrus) plays a role in second language acquisition.
  154. [154]
    An fMRI Study of Late Learners of American Sign Language - Frontiers
    As described in section fMRI Results: L2 ASL vs. L1 English, the regions identified were in the left inferior frontal gyrus, left anterior and posterior ...Missing: EEG | Show results with:EEG
  155. [155]
    [PDF] Second-Language Phonology Learning and Neuroplasticity
    Jan 1, 2008 · We argue for a separation between language learning and language acquisition. We also present a new model for adult L2 learning, called the ...
  156. [156]
    The Plastic Bilingual Brain: Synaptic Pruning or Growth ...
    Aug 6, 2025 · Humans appear to have a critical period (CP) for language acquisition: Second language (L2) acquisition becomes harder after early childhood ...
  157. [157]
    Brain gray matter morphometry relates to onset age of bilingualism ...
    Feb 8, 2024 · In this study, we show the brain structural correlates that are associated with second language age of acquisition (L2AoA) and theory of mind.Missing: period | Show results with:period
  158. [158]
    A critical period for second language acquisition: Evidence from 2/3 ...
    The results support the existence of a sharply-defined critical period for language acquisition, but the age of offset is much later than previously speculated.
  159. [159]
    Bilingualism and the Development of Executive Function: The Role ...
    This paper reviews research examining the effect of bilingualism on children's cognitive development, and in particular, executive function.
  160. [160]
    Frequent L2 language use enhances executive control in bilinguals
    May 18, 2016 · Seminal research which indicates that bilingualism leads to enhanced executive control (Bialystok, Craik, Green & Gollan, 2009; Bialystok ...
  161. [161]
    How does bilingualism modify cognitive function? Attention to the ...
    Jan 28, 2022 · It has been claimed that bilingual experience leads to an enhancement of cognitive control across the lifespan.<|separator|>
  162. [162]
    Disinhibition enables vocal repertoire expansion after a critical period
    Aug 31, 2024 · We predict that suppressing the influence of these interneurons in adult zebra finches could re-open the critical period, allowing them to learn new syllables.Missing: suspension | Show results with:suspension
  163. [163]
    From songbird to humans: The multifaceted roles of FOXP2 in ...
    This review explores the intricate relationship between FOXP2, motor learning, and speech in an anatomical and functional context.Missing: suspension | Show results with:suspension
  164. [164]
    AI-driven chatbots in second language education: A systematic ...
    AI chatbots promoted contextual vocabulary use and natural conversational flow through integrated vocabulary missions, quizzes, and real-time correction. Yang ...<|separator|>
  165. [165]
    Duolingo Introduces AI-Powered Innovations at Duocon 2024
    Sep 24, 2024 · These new features—Video Call and Adventures—demonstrate Duolingo's commitment to leveraging cutting-edge AI to enhance the learning experience ...Missing: enhancements correction
  166. [166]
    http://investors.duolingo.com/news-releases/news-release-details/duolingo-introduces-ai-powered-innovations-duocon-2024
  167. [167]
    High‐Immersion Virtual Reality for Pragmatics Development
    May 26, 2025 · First, it provides an overview of the potential of VR for pragmatics development. Second, it offers examples of existing studies on VR for ...
  168. [168]
    exploring the impact of virtual reality exposure on foreign language ...
    Aug 19, 2025 · This study examines the relationships between virtual reality (VR) exposure, communicative confidence, perceived fluency, and foreign ...
  169. [169]
    A Comparative Analysis of Machine Learning Models for Predicting ...
    Aug 4, 2025 · This study aims to evaluate the performance of various machine learning models for predicting English as a foreign language student performance
  170. [170]
    (PDF) Unpacking Cultural Bias in AI Language Learning Tools
    Feb 8, 2025 · AI programs that help us learn languages are commonly used in various classrooms; however, they often include some forms of prejudice ...Missing: L1s | Show results with:L1s
  171. [171]
    [PDF] Language variation and algorithmic bias - ACM FAccT
    Jun 24, 2022 · Error rates varied greatly by L1 (and individual) for both systems, but they were lowest for L1 speakers of English21. Age of second language ...
  172. [172]
    Linguistic and Geographic Diversity in Research on Second ...
    May 22, 2023 · The present study assesses linguistic and geographic diversity in selected outlets of SLA and multilingualism research.
  173. [173]
    [PDF] Pedagogical struggles and gaps in language literacy enhancement
    The lack of basic language skills and difficulties of the indigenous learners in learning a new language only show that they have low readiness and literacy ...
  174. [174]
    [PDF] Indigenous Language Loss, Barriers to Acquisition, and Relationality
    This study explores Indigenous language loss, barriers to acquisition, and how this loss impacts relations, including to Mother Earth and other beings of ...<|separator|>
  175. [175]
    The Impact of Synchronous, Asynchronous, and Hybrid Learning ...
    Aug 21, 2025 · Findings: The results showed that the hybrid learning model yielded the highest post-test motivation scores among EFL learners, followed by the ...
  176. [176]
    The predictive effect of extrinsic motivation on English online ...
    Aug 28, 2025 · This study investigates the predictive role of extrinsic motivation on online learning engagement among Chinese non-English-major ...
  177. [177]
    Full article: Learning from the pandemic and looking into the future
    Jul 2, 2024 · This special issue presents a collection of empirical studies conducted in various contexts, aiming to uncover the challenges faced by language learners
  178. [178]
    Language skills of adults with dyslexia in English as a foreign ...
    Mar 26, 2025 · There are some studies suggesting that people with dyslexia have difficulties not only in word reading and spelling but also in reading and oral ...Missing: neurodiversity | Show results with:neurodiversity
  179. [179]
    Teaching at the intersection: Bilingualism and neurodiversity
    For instance, a student with dyslexia may struggle more with a second language if foundational concepts in their first language are not well established.
  180. [180]
    New UNESCO report calls for multilingual education to unlock learning
    Feb 18, 2025 · Today, 40 % of people globally lack access to education in the language they speak and understand fluently. In some low- and middle-income ...Missing: equity | Show results with:equity
  181. [181]
    Issues of Equity and Access in Foreign Language Education
    Nov 8, 2024 · In this chapter, I examine issues of equity and access in foreign language education through a comparative, justice-oriented lens.
  182. [182]
    A qualitative study on ethical issues related to the use of AI-driven ...
    Jul 31, 2025 · The aim of the research is to provide a clear overview of the potential risks that could be related to the use of AI-driven apps in foreign ...
  183. [183]
    Elevating the cultural wealth of multilingual students, families, and ...
    Multilingual learners often possess first-hand experiences and knowledge of climate change–either as a climate refugee or as a member of a migrant community ...Missing: second acquisition
  184. [184]
    [PDF] Big Data in SLA: advances in methodology and analysis
    Big data are particularly helpful for empirical investigations of the complex interactions of standard SLA variables, which smaller scale lab or field-based ...