Split infinitive

A split infinitive is a construction in English grammar in which an adverb, adverbial phrase, or other modifier intervenes between the infinitive marker "to" and the base form of the verb, as in the phrase to boldly go from the Star Trek opening narration.^[1]^[2] This structure contrasts with unsplit forms like to go boldly, and it typically occurs when the modifier provides emphasis, clarity, or idiomatic flow to the infinitive phrase.^[3]^[4] Examples include to quickly decide or to really understand, where repositioning the adverb might result in awkward or ambiguous phrasing.^[1]^[5] The controversy surrounding split infinitives arose in the mid-19th century, when grammarians like Henry Alford in his 1864 book The Queen's English condemned them as ungrammatical, drawing an analogy to Latin infinitives, which are single words (e.g., amare for "to love") and thus incapable of splitting.^[2]^[5] This prescriptive rule gained traction during the Victorian era as part of broader efforts to impose classical Latin structures on English, despite evidence that split infinitives had appeared sporadically since the 13th century and were absent from earlier English literature by authors like Shakespeare or in the King James Bible.^[3]^[2] By the early 20th century, critics such as the Fowler brothers in their 1907 The King's English dismissed the prohibition as overstated, noting its lack of basis in natural English usage.^[2] In contemporary English, split infinitives are widely accepted by authoritative style guides and linguists when they improve readability or precision, as avoiding them can sometimes distort meaning or produce clumsier alternatives.^[3]^[5] For instance, the Chicago Manual of Style explicitly rejects any blanket rule against them, while H.W. Fowler's A Dictionary of Modern English Usage (1926) advocates their use for emphasis.^[3] In formal writing, they may still be avoided to appease traditionalist readers, but in general prose, journalism, and speech, they are commonplace and no longer viewed as errors.^[4]^[5]

Definition and Usage

What Is a Split Infinitive

A split infinitive is a grammatical construction in English where an adverbial modifier, such as an adverb or adverb phrase, is inserted between the particle "to" and the base form of the verb in an infinitive phrase. For example, in the phrase "to quickly run," the adverb "quickly" separates "to" from "run," creating the split.^[6] This placement disrupts the traditional unity of the infinitive form but does not alter the core semantic meaning of the verb phrase, though it can affect emphasis or clarity in context. In English grammar, the infinitive is the base, uninflected form of a verb, typically marked by "to" followed directly by the verb, as in "to run" or "to eat," functioning as a noun, adjective, or adverb in sentences.^[7] The term "infinitive" derives from the Late Latin infinitivus, meaning "unlimited" or "undefined," reflecting its lack of specific tense, person, number, or mood limitations, a concept adopted into English grammatical terminology around the 1510s.^[8] Splitting occurs when an intervening element, most commonly an adverb of manner (e.g., "boldly" in "to boldly go") or degree (e.g., "really" in "to really understand"), is placed between these components, potentially for rhythmic or emphatic effect.^[6] To identify a split infinitive, look for any modifier—primarily adverbial—that interrupts the "to + verb" sequence in an infinitive construction, ensuring the interruption does not stem from unrelated syntactic elements like objects or complements outside the core infinitive. While adverbs are the typical splitters, other elements such as adverbial phrases (e.g., "to more fully appreciate" in formal writing) can occasionally perform a similar role, though such cases are less standard and often context-dependent. This structure is recognizable in both formal and informal English, where it may enhance natural flow without grammatical error.^[6]^[1]

Examples in English Sentences

A prominent canonical example of a split infinitive is the phrase "to boldly go," featured in the opening narration of the television series Star Trek: "Space: the final frontier. These are the voyages of the starship Enterprise. Its five-year mission: to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before."^[9] This construction places the adverb "boldly" between "to" and "go," emphasizing the manner of exploration.^[10] In everyday sentence contexts, split infinitives appear in various positions to modify the verb's action clearly. For instance, as an object of a verb, consider: "He asked me to carefully read the statute."^[11] Here, "carefully" splits "to read," highlighting the precision required in the reading. As part of an adverbial phrase, the sentence "The women proceeded to briefly describe what they'd seen in the city" uses "briefly" to split "to describe," underscoring the conciseness of the description.^[1] Another example in a subject-related context is: "She decided to slowly open the door," where "slowly" intervenes in "to open" to convey deliberate caution.^[12] Variations in modifiers further illustrate the flexibility of split infinitives, ranging from single adverbs to phrases. A simple adverb split occurs in "She wishes to really understand his motives," with "really" emphasizing genuine comprehension.^[13] For a more complex adverbial phrase, "The employer intended to at least try to explore possible reasonable accommodations" inserts "at least" to split "to try," stressing minimal effort while maintaining clarity in the intended action.^[14] Similarly, phrases like "to better serve our customers" position "better" as a comparative adverb to split "to serve," often used in service-oriented contexts to highlight improved dedication.^[15] These examples demonstrate how split infinitives can emphasize the modifying element, such as the adverb's intensity or scope, without altering the sentence's core meaning, thereby enhancing stylistic focus in natural English usage.^[14] For instance, in "I vow to, whenever possible, split infinitives," the interrupting phrase "whenever possible" splits "to split," drawing attention to the conditional nature of the commitment.^[16]

Historical Development of the Construction

Origins in Old and Middle English

In Old English (c. 450–1150), the infinitive form of verbs was a single, undecomposable word typically ending in -an, such as gān ("to go") or singan ("to sing"), rendering any form of splitting structurally impossible.^[17] This morphology stemmed from Proto-Germanic roots, where infinitives functioned as nominal forms with a consistent suffix, lacking the separable particle structure seen in some other language families.^[18] Although the preposition tō could precede the infinitive to form a tō-infinitive construction—often marked with dative case and behaving like a prepositional phrase—modifiers such as adverbs or particles were positioned externally, either before tō or after the verb, rather than inserted between them.^[19] For instance, in the epic poem Beowulf, infinitival forms like gān or tō gānne appear without internal modification, reflecting the construction's nominal character and resistance to decomposition.^[20] The Germanic linguistic heritage reinforced this undecomposability, as Proto-Germanic infinitives were inherited as integrated verbal-nominal units without opportunities for adverbial intrusion, in contrast to Romance languages like Latin, where infinitives were also single words but part of a broader typological framework allowing different modifications.^[21] Prefixes (e.g., for- in forgīetan, "to forget") or particles could attach to the infinitive stem, but these were fused elements, not separable insertions akin to later splits.^[17] This period thus established a foundation of verbal integrity that persisted into early Middle English, with no attested instances of split forms in surviving Old English texts. During the Middle English period (c. 1150–1500), the to-infinitive construction solidified as the dominant form, evolving from its Old English prepositional origins into a more verbal category, yet modifiers continued to be pre- or post-posed rather than inserted between to and the verb stem.^[22] The influence of Old Norse contact introduced potential syntactic flexibility, with early split infinitives emerging sporadically in northern dialects by the 13th century, such as "for to him reade," but these were exceptional and not normative in southern or standardizing texts.^[23]^[17] In Geoffrey Chaucer's The Canterbury Tales (late 14th century), infinitives typically follow non-split patterns, as in "Som man desireth for to han richesse" ("Some man desires for to have riches"), where "for to" precedes the bare verb han without adverbial separation.^[24] Other constructions, such as "to goon" or "to seen," similarly place any modifiers externally, illustrating the period's adherence to undecomposed forms amid ongoing grammatical shifts toward analytic structures.^[25] This transitional phase highlights the gradual erosion of the Old English infinitive's nominal rigidity under Norman influences, setting preconditions for fuller splittability in subsequent eras.

Evolution in Early Modern English

During the 16th and 17th centuries, split-like constructions in English infinitives remained rare, appearing sporadically in prose and verse as transitional forms that bridged medieval flexibility with emerging modern syntax. These insertions, often involving adverbs placed near or within the infinitive marker "to," reflected tentative explorations of word order amid the period's linguistic experimentation. For instance, Thomas More employed a clear split in his Confutation of Tyndale (1532), writing "tyll men . . . fell to forgete them . . . and then to not byleue them," where "not" intervenes between "to" and "byleue." Similarly, Thomas Stapleton used "to flatly gainsaye" in his A Countercise (1565), positioning the adverb "flatly" directly after "to."^[26] The advent of printing in England, beginning with William Caxton's press in 1476, played a pivotal role in standardizing written forms and influencing infinitive usage by promoting consistent dialectal choices, particularly the London-based East Midlands variety. Caxton's editions of works like Chaucer's Canterbury Tales (c. 1478) and his own translations, such as Eneydos (1490), showcased evolving periphrastic constructions, including causative structures like "ded do shewe," which paralleled the growing acceptance of auxiliary verbs and flexible modifier placement in infinitives. This standardization reduced regional variants in infinitive forms, fostering a more uniform platform for adverbial insertions, though splits remained uncommon in printed literary texts of the era. Building briefly on Middle English precursors, where such constructions were more frequent in authors like Reginald Pecock, Early Modern writers adapted these patterns selectively.^[26] Linguistically, this period marked a broader shift from synthetic to analytic structures in English, enabling greater modifier flexibility around infinitives as reliance on inflections diminished in favor of word order and auxiliaries. The rise of non-finite clauses, including to-infinitives and -ing forms, allowed adverbs to approach or enter infinitive phrases more readily, as seen in the periphrastic do-constructions and negation patterns that regularized adverb placement. This analytic trend, evident in Elizabethan prose and drama, laid groundwork for later normalization without yet producing widespread splits, prioritizing clarity in emerging standardized syntax over rigid Latin-inspired models.^[26]

Emergence in Modern English

In the 19th century, split infinitives began to re-emerge and gain traction in English prose, marking a shift from their relative rarity in earlier periods. Linguistic corpora such as the Corpus of Historical American English (COHA) reveal a notable increase in frequency during this era, with instances rising from around 4.50 per million words in the 1830s to a peak of 33.27 per million words in the 1880s.^[27] This rise reflects broader trends in literary expression. By the 20th century, split infinitives achieved greater normalization, particularly in journalism, spoken language, and modern literature, as prescriptive rules against them waned. COHA data indicate a temporary decline to a low of 10.68 instances per million words in the 1940s, followed by a sharp resurgence post-1950, reaching 75.69 per million in the 1990s and 97.13 in the 2000s, demonstrating their commonality in contemporary usage.^[27] Authors like Ernest Hemingway employed them deliberately, as in "to really live."^[28] Corpora like the British National Corpus (BNC) and Corpus of Contemporary American English (COCA) confirm high frequencies in spoken and written media, with thousands of occurrences for common splitters like "to just" or "to really."^[29] Several factors contributed to this emergence, rooted in the evolution of English toward a more analytic syntax that allows greater adverb mobility. Unlike synthetic languages such as Latin, modern English permits adverbs to insert freely for emphasis and idiomatic expression, a trait more pronounced in spoken language than formal writing.^[27] The decline of strict prescriptivism after the mid-20th century further promoted acceptance, as focusing adverbs (e.g., "just," "actually") increasingly split infinitives to reflect natural speech patterns, shifting from earlier manner adverbs.^[27] This trend underscores how split infinitives enhance clarity and rhythm, aligning with the language's analytic flexibility.^[29]

Linguistic Theories on Origins

Analogical Explanations

One prominent analogical theory suggests that split infinitives emerged through extension from patterns in finite verb constructions, where adverbs commonly intervene between auxiliary verbs and main verbs, as in "has not gone" or "does not really want." This syntactic flexibility in auxiliary-verb clusters provided a model for adverb placement between "to" and the infinitive form, treating "to" analogously to an auxiliary.^[29] Historical linguist Otto Jespersen advanced this view, arguing that split infinitives reflect the natural analogy inherent in English word order, driven by the language's tolerance for adverbial insertions to enhance clarity and rhythm. In his analysis, Jespersen traces the construction to parallels like the shift from adverbial phrases such as "with the object of further illustrating the matter" and finite examples like "he further illustrates" or "that he may further illustrate," culminating in infinitival forms like "in order to further illustrate."^[29] Additional analogies extend to other multi-element phrases in English, including prepositional constructions like "from the house out," where particles or adverbs separate from their heads, and broader adverb-verb clusters that demonstrate a pattern of splitting verbal units for emphasis or idiomatic flow. These parallels underscore a systemic tendency in English to prioritize semantic clarity over rigid adjacency in phrase structure.^[30] Diachronic evidence supports this gradual adoption via analogy, with early modern examples appearing sporadically before gaining traction in the 19th century. For instance, 19th-century authors such as Charlotte Brontë in Jane Eyre (1847) and Charles Dickens in David Copperfield (1850) employed split infinitives, illustrating the construction's integration into literary prose through familiar verbal patterns.^[30]

Transformational Grammar Analyses

In the framework of transformational-generative grammar pioneered by Noam Chomsky, split infinitives arise from deep structures in which the infinitive phrase functions as a unified constituent, typically represented with "to" as an infinitival marker governing a verb phrase (VP). Adverbs are introduced through transformational rules or adjunction operations that optionally insert them between "to" and the verb, generating surface forms like "to boldly go" without violating core syntactic principles. This process reflects the grammar's capacity to derive varied outputs from underlying representations, where adverb placement enhances scope or emphasis while preserving semantic relations. Phrase structure rules in this model accommodate split infinitives by allowing hierarchical representations such as [to [AdvP [VP V ...]]], where the adverb phrase (AdvP) adjoins to the VP, enabling optional movement or base-generation in that position. This structure treats "to" not as a rigid prefix but as a functional element that licenses the VP, permitting adverb intervention as a licit option rather than an anomaly. Geoffrey K. Pullum's 1982 analysis reinforces this by positing that infinitival "to" is syncategorematic—lacking independent categorial status and failing to form a strict constituent with the verb alone—thus explaining why adverbs can freely separate them in constructions like "to really understand" without constituency violations.^[31]

Variations and Types

Simple Adverb Splits

A simple adverb split infinitive is a grammatical construction in English where a single adverb is inserted between the infinitive marker "to" and the base form of the verb, resulting in structures such as "to quickly run" or "to boldly go."^[14] This placement disrupts the traditional adjacency of "to" and the verb but maintains syntactic coherence within the infinitive phrase.^[32] Common adverbs in these splits include those of manner, such as "quickly" or "boldly," which describe how the action is performed (e.g., "to run fast"), and intensifiers like "really" or "very," which emphasize the verb's degree (e.g., "to really try").^[33] Corpus studies highlight "really" and "better" as particularly frequent, with "really" accounting for up to 31% of splitters in some datasets.^[34] Syntactically, these adverbs occupy positions within the verb phrase (VP), functioning as direct modifiers of the infinitive verb in adverbial roles of manner, degree, or focus, without introducing subordinate elements or multi-word phrases that could complicate the structure.^[29] This simplicity allows the adverb to integrate seamlessly into the infinitive's core, often enhancing clarity or emphasis in contemporary usage. Frequency data from large corpora, such as the Corpus of Contemporary American English (COCA), demonstrate that simple adverb splits predominate across genres like blogs, academic writing, and speech.^[32] For instance, in COCA's over 1 billion words (as of 2022), the single-adverb split "to better understand" appears 791 times in academic texts alone.^[35]^[32]

Complex Element Splits

Complex split infinitives extend beyond single-word insertions by incorporating multi-word modifiers, such as adverb phrases or prepositional phrases, between "to" and the verb. These phrasal splits often involve adverbial phrases like "more than" or "at least partly," creating constructions such as "to more than double profits" or "to at least partly respond to the crisis."^[29] Such forms are documented in large corpora like COCA, indicating their validity in contemporary usage despite their relative rarity compared to simple adverb splits.^[35] Prepositional inserts represent another subtype, though less common, where phrases like "on average" intervene, as in "to on average halve pay rates."^[36] Clause-like elements further complicate these structures, appearing in rare cases such as "to not only just go but also stay," where correlative constructions split the infinitive to emphasize contrast or addition.^[29] These advanced forms maintain grammatical integrity but occur infrequently.^[29] Complex splits carry inherent constraints, primarily due to their length, which can limit readability and introduce awkwardness. For instance, elaborate insertions like "to gradually, systematically, and economically relieve" were accepted by only 23% of the American Heritage Usage Panel in 1988, as they risk overloading the infinitive and disrupting sentence flow.^[37] In technical writing, such as economic reports, phrasal splits like "to more accurately reflect market conditions" enhance precision without excessive complexity.^[29] Modern literature and poetry occasionally employ these for stylistic effect, as seen in Kayla Perrin's novel where "to quickly head to the house" conveys urgency in narrative prose.^[36] Similarly, in technical contexts like financial analysis, Eric Dash's reporting uses "to on average halve pay" to succinctly describe corporate strategies.^[36] These examples illustrate how complex splits, when judiciously applied, support clarity in specialized genres.

History of the Term

Coinage and Early Usage

The specific term "split infinitive" first appeared around 1890 as a label for the construction in which an adverb or other element intervenes between the particle "to" and the base form of the verb, such as "to boldly go." Although the construction itself had appeared sporadically since the 13th century, criticisms of it as a grammatical error developed in English grammatical discourse during the 19th century, with related phrasing like "splitting the infinitive" emerging in the 1860s.^[38] Early discussions of adverb placement with infinitives appeared in grammatical treatises. For instance, Goold Brown addressed the issue in his comprehensive The Grammar of English Grammars (1851 edition), arguing against unnecessary separation for clarity, though he viewed the practice as acceptable in certain contexts to avoid ambiguity and did not use the phrase "split infinitive." A prominent early criticism came from Henry Alford, Dean of Canterbury, in his 1864 book The Queen's English. Responding to a correspondent's query about inserting adverbs between "to" and the verb, such as in "to scientifically illustrate," Alford condemned the practice, stating it was "entirely unknown to English speakers and writers." Alford's influential work framed the insertion as an undesirable innovation, helping to establish it as a point of prescriptive concern. By the 1860s and 1870s, related terminology spread through periodicals and style guides, where it was adopted as shorthand for the perceived "error." Publications like The Contemporary Review and other literary journals referenced "splitting the infinitive" in discussions of proper English usage, often echoing Alford's views that it violated traditional syntax. This early adoption solidified the concept's role in 19th-century prescriptivism, positioning it as a marker of refined versus careless writing.

Evolution of Terminology

In the early 20th century, the term "split infinitive" retained its pejorative connotation as a marker of grammatical error within prescriptive linguistic traditions, reflecting ongoing debates over English syntax influenced by classical models. However, by 1926, H. W. Fowler's A Dictionary of Modern English Usage signaled a pivotal shift, portraying excessive aversion to the construction as irrational and labeling its detractors "bogy-haunted creatures," thereby elevating the term toward a more neutral descriptor in scholarly and usage discussions. Alternative designations emerged alongside "split infinitive," with "cleft infinitive" appearing as early as 1893 to describe the same intervening adverbial structure, though it waned in prevalence after 1905 and is now largely obsolete in mainstream grammars.^[30] Less commonly, terms like "intervening infinitive" have appeared in specialized analyses to emphasize the placement of elements between "to" and the verb base.^[39] Global variations in terminology usage highlight divergences between American and British English style debates, where American linguistic corpora show higher incidences of the construction—and thus more frequent invocation of the term—in informal registers, contrasting with British prescriptivist emphases on avoidance in formal writing.^[40] Corpus-based digital analyses, such as those from the Corpus of Historical American English (COHA), reveal that discussions of the term peaked in relevance during the mid-20th century, with the construction's frequency rising from 9.98 per million words in the 1940s to 16.8 per million in the 1950s, aligning with the broader decline of rigid prescriptivism and the rise of descriptivist linguistics that neutralized the term's error status.^[41]

The Controversy Over Split Infinitives

Historical Timeline of Debate

The debate surrounding split infinitives gained initial traction in the mid-19th century amid growing prescriptive approaches to English grammar. Early criticisms appeared sporadically in reviews and grammars during the 1850s and 1870s, with Henry Alford's 1864 publication A Plea for the Queen's English serving as a seminal work that condemned the construction as ungrammatical, thereby amplifying public awareness and opposition.^[42]^[10] By the 1880s and into the early 1900s, the controversy intensified alongside broader education reforms that emphasized standardized grammar instruction in schools, where prohibitions against split infinitives were routinely included in curricula and textbooks to enforce uniformity in written English.^[43] Traditional grammars of the era, such as those by Richard Meade Bache and others, reinforced these bans, embedding the rule in pedagogical materials across Britain and the United States.^[44] The peak of the debate unfolded from the 1920s through the 1950s, as influential style manuals codified the avoidance of split infinitives for clarity and elegance in prose. William Strunk Jr.'s The Elements of Style (1918), widely adopted in educational settings, explicitly advised that while historical precedent existed for the construction, it should generally be avoided unless the adverb enhanced meaning.^[45] From the 1960s onward, the prescriptive stance waned with the ascendance of descriptivist linguistics, which treated split infinitives as a legitimate and idiomatic feature of evolving English usage. This shift was underscored by the 1961 release of Webster's Third New International Dictionary, a descriptivist landmark that refrained from marking the construction as incorrect, signaling broader acceptance in authoritative references.^[46]

Key Figures and Publications

Henry Alford, Dean of Canterbury, played a pivotal role in popularizing opposition to split infinitives through his 1864 book A Plea for the Queen's English: Stray Notes on Speaking and Spelling, where he critiqued the insertion of adverbs between "to" and the verb as a disruption of the infinitive's integrity.^[47] Alford argued that such constructions violated the analogy of English grammar, treating "to" as an inseparable part of the infinitive form, and his work marked a seminal prescriptivist attack that influenced subsequent usage debates. H. W. Fowler and his brother F. G. Fowler advanced a more nuanced perspective in their 1906 usage guide The King's English, defending the occasional use of split infinitives when they enhance clarity or emphasis, such as in "to really understand" to stress the adverb.^[48] The Fowlers contended that rigid avoidance could lead to awkward phrasing and that splits serve a useful purpose in natural expression, positioning their text as a counterpoint to stricter prescriptivism.^[48] The Danish linguist Otto Jespersen contributed extensively to the debate across his multi-volume A Modern English Grammar on Historical Principles (1909–1949), advocating for split infinitives as a natural evolution of English syntax rather than a grammatical error.^[49] Jespersen emphasized the language's organic flexibility, arguing that prescriptive prohibitions against splits were artificial impositions not aligned with historical usage or clarity, and he challenged the very concept of the infinitive as a fixed unit including "to."^[29] In the American context, Ambrose Bierce reinforced prohibitions in his 1909 handbook Write It Right: A Little Blacklist of Literary Faults, explicitly condemning split infinitives as faults that obscure meaning, such as advising against "to boldly go" in favor of "to go boldly."^[50] Bierce's concise, satirical style amplified prescriptivist views on the East Coast, influencing early 20th-century American style guides.^[50]

Arguments Against Split Infinitives

Claims from Infinitive Integrity

The claims from infinitive integrity assert that the English infinitive, comprising the particle "to" and the base verb form, functions as a unified grammatical construct equivalent to a compound word, and any insertion between these elements—such as an adverb—disrupts its wholeness and renders it defective. Proponents of this view, particularly in 19th-century prescriptive grammar, argued that the infinitive exists in a "full" or "perfect" state only when intact, likening splitting to an act of corruption that undermines the form's structural coherence.^[5] This perspective gained traction in the 19th century, building on 18th-century efforts to systematize English verb forms, where grammarians classified the "to"-infinitive as a discrete, indivisible part of speech akin to other fixed verbal units. Although early works like Robert Lowth's A Short Introduction to English Grammar (1762) did not explicitly address splitting, they contributed to viewing the infinitive as a cohesive entity by emphasizing its role as a complete non-finite verb form without allowance for internal modification. By mid-century, this evolved into outright objection, as seen in Henry Alford's A Plea for the Queen's English (1864), which condemned split constructions as violations of the infinitive's essential unity.^[14]^[51] The argument's logic falters, however, upon recognizing that English infinitives lack the morphological fusion found in some other languages, where infinitive markers and verbs blend into single words; in English, "to" remains a distinct particle preceding the unaltered base verb, forming a phrasal rather than compounded structure. This distinction highlights the artificiality of insisting on indivisibility, as the construction inherently permits adverbial placement for emphasis without altering the verb's core form. A paradigmatic example is "to boldly go," frequently critiqued for severing the supposed bond between "to" and "go," thereby compromising the infinitive's purported integrity.^[52]

Influences from Latin and Greek

In Latin, the infinitive is an indecomposable single word that incorporates the sense of "to" within its form, such as amare for "to love" or esse for "to be," making it impossible to insert an adverb between components.^[5] This fused structure led early English grammarians, particularly during the Renaissance when Latin served as the model for vernacular grammars, to view the English infinitive—"to" plus the verb—as an analogous unit that should remain unsplit to preserve classical purity.^[41] Parallels exist in Ancient Greek, where infinitives in Attic dialect are likewise single fused words, such as λύειν (lyein) for "to loose" or φέρειν (pherein) for "to carry," without provision for adverbial insertion. Renaissance scholars, educated in both Latin and Greek classics, extended this logic to English grammar, reinforcing prescriptive rules through grammars that prioritized the undecomposable nature of classical verb forms.^[41] The 19th-century revival of these classical ideals, especially among Victorian educators, intensified objections to split infinitives as a deviation from the synthetic precision of Latin and Greek.^[29] Figures like Henry Alford in The Queen's English (1864) explicitly invoked Latin models to condemn constructions such as "to scientifically illustrate," promoting a "classical purity" that aligned English more closely with ancient languages.^[5] However, linguists have critiqued this imposition, noting that English's analytic structure—relying on separate particles like "to"—naturally allows for adverb placement in ways incompatible with the fused infinitives of synthetic languages like Latin and Greek.^[29] As Steven Pinker observes, prohibiting splits in English to match Latin "makes about as much sense as forcing modern residents of England to wear laurels and togas."^[29]

Prescriptivist Critiques

Prescriptivists have long criticized split infinitives on aesthetic grounds, viewing them as disruptive to the natural flow and euphony of English prose. In his 1906 guide A Desk-Book of Errors in English, Frank H. Vizetelly described the construction as "reprehensible," arguing that inserting an adverb between "to" and the verb, as in "to carefully examine," mars the unity of the infinitive form and produces clumsy phrasing that offends refined sensibilities.^[53] This perspective echoed broader traditionalist concerns that such splits create an "ugly" interruption, prioritizing rhythmic harmony over emphatic placement.^[53] During the 19th century, opposition to split infinitives also carried social connotations, associating the construction with uneducated or lower-class speech in debates over linguistic propriety. Grammar authorities of the era positioned avoidance of splits as a marker of cultivated status, contrasting it with the vernacular habits deemed vulgar by the elite.^[54] This stigma reinforced class distinctions, as prescriptivists like those in early usage manuals warned that employing splits signaled a lack of formal training, thereby perpetuating hierarchies in educational and social contexts.^[54] The codification of bans on split infinitives often lacked empirical grounding, relying instead on arbitrary assertions of correctness. Alfred Ayres, in his 1881 work The Verbalist, exemplified this by prohibiting the construction without citing historical or linguistic evidence, simply deeming it an error to be eradicated in polite usage. Such rules proliferated in 19th-century grammars, establishing the split as a shibboleth despite its longstanding presence in English literature. In the 21st century, prescriptivist resistance persists among conservative media and commentators, who uphold the ban as a bulwark against linguistic decay. Publications aligned with traditionalist views, such as those critiquing modern journalism, decry split infinitives in news reports as evidence of declining standards, linking them to broader cultural conservatism.^[55] This "new prescriptivism," resurgent under conservative political influences in Britain since the 2010s, frames avoidance of splits as essential to maintaining authoritative discourse.^[56]

Modern Perspectives

Descriptivist Linguistic Views

Descriptivist linguistics emphasizes the observation and documentation of how native speakers actually use language in natural contexts, rather than enforcing normative rules derived from classical languages or arbitrary conventions. In this approach, split infinitives are regarded as a legitimate and idiomatic feature of modern English, reflecting the flexibility of adverb placement to achieve clarity, emphasis, and rhythmic flow without disrupting grammatical integrity. Linguists argue that such constructions arise organically in spoken and written English, serving communicative purposes that rigid avoidance would hinder. Corpus-based studies provide empirical support for the prevalence of split infinitives, demonstrating their increasing acceptance and frequency in contemporary usage. For instance, analysis of large-scale corpora like the British National Corpus reveals that split infinitives occur infrequently overall, but this rate rises notably in informal registers such as conversation, where they appear more frequently than in formal writing to accommodate natural adverb-verb adjacency. Douglas Biber and colleagues, in their comprehensive examination of spoken and written English, highlight how adverbial elements commonly intervene in infinitive constructions during speech, underscoring splits as a normative pattern rather than an error. Similarly, investigations into World Englishes show splits are more attested in spoken data across varieties, affirming their role in idiomatic expression.^[57] Prominent descriptivists Rodney Huddleston and Geoffrey K. Pullum, in their influential The Cambridge Grammar of the English Language (2002), explicitly endorse split infinitives as fully grammatical and often stylistically superior, rejecting prescriptivist bans as unfounded relics of 19th-century pedantry. They note that separating the infinitive marker "to" from the verb with an adverb—such as in "to boldly go"—is commonplace in both speech and writing, enhancing precision without violating syntactic principles.^[58]

Usage in Contemporary Style Guides

Contemporary style guides largely reflect descriptivist linguistic principles, which view split infinitives as a natural feature of English rather than a grammatical error, allowing their use when it enhances clarity or emphasis.^[59] The Associated Press (AP) Stylebook, in its updates through the 2020s, advises that splitting an infinitive is often necessary to convey precise meaning or ensure a sentence reads clearly, moving away from earlier cautions against awkward constructions.^[60] For instance, it permits phrases like "to quickly run" if rephrasing would alter the intended sense or rhythm. The Chicago Manual of Style (18th edition, 2024) accepts split infinitives and has not frowned on them since the 13th edition (1983), permitting their use without any general preference to avoid them, especially when it avoids ambiguity or improves readability.^[61]^[62] This approach emphasizes that the construction is not inherently wrong and has been acceptable in formal writing for decades.^[63] The Modern Language Association (MLA) Handbook takes a neutral stance on split infinitives, advising writers to prioritize clarity and natural expression over rigid avoidance, deeming them generally acceptable in academic prose. Similarly, the American Psychological Association (APA) Publication Manual (7th edition, 2020) does not address split infinitives at all, implying no prohibition and leaving decisions to stylistic judgment focused on precision and flow. (Note: APA's silence aligns with broader guidelines on verb forms, confirming neutrality.) British style guides tend to be more permissive than some conservative American ones. The Guardian Style Guide, for example, states that it is "perfectly acceptable, and often desirable, to sensibly split infinitives," citing "to boldly go" as an elegant example that enhances phrasing without causing awkwardness.^[64] Overall, these guides underscore a consensus that split infinitives should be evaluated based on context rather than blanket rules.

Practical Guidance

Strategies for Avoidance

For writers who prefer to adhere to traditional grammatical conventions in formal contexts, several strategies exist to rephrase sentences containing split infinitives, primarily by repositioning modifying words or restructuring the clause to preserve meaning without inserting an adverb between "to" and the verb.^[12] These approaches are recommended in style guides and writing tutorials for maintaining clarity and avoiding perceived errors, though they require attention to ensure the revised sentence flows naturally.^[1] One common technique is to reposition the adverb either before the infinitive marker "to" or after the base verb, depending on which placement best suits the sentence's rhythm and emphasis. For instance, the split infinitive in "She decided to instantly quit her job" can be revised to "She decided to quit her job instantly," moving the adverb to the end for a smoother read.^[12] Similarly, "It’s hard to completely follow his reasoning" becomes "It’s hard to follow his reasoning completely," which avoids the split while retaining the original intent.^[12] Pre-positioning the adverb, as in "Instantly to quit her job would be unwise," is less common and can sound archaic or stiff, but it works in certain emphatic constructions.^[1] Another effective method involves restructuring the clause using alternative verb forms, such as gerunds, finite verbs, or nominal phrases, to eliminate the infinitive altogether. In the example "He plans to carefully review the document," this can be rephrased as "He plans a careful review of the document," substituting a noun phrase for the infinitive to convey the same action without splitting.^[1] For more complex sentences, converting to a finite verb clause helps: "The team needs to boldly explore new markets" shifts to "The team needs bold exploration of new markets," though this may introduce slight formality.^[65] A side-by-side comparison illustrates these options:

Original (Split)	Repositioned Adverb	Restructured Clause
To boldly go where no one has gone before	To go boldly where no one has gone before	Going boldly where no one has gone before
She wants to really learn the skill	She wants to learn the skill really	She wants real learning of the skill

These revisions, drawn from practical grammar resources, demonstrate how avoidance can align with prescriptivist preferences.^[1]^[12] While these strategies promote grammatical conformity, they are not without drawbacks; repositioning or restructuring can sometimes diminish emphasis on the adverb or lead to reduced clarity in the sentence. For example, avoiding the split in "Gemma asked Kamil to just be himself" by changing it to "Gemma asked just Kamil to be himself" alters the meaning, implying exclusivity rather than simplicity. In such cases, the non-split version introduces ambiguity or awkwardness, potentially requiring further adjustments that complicate the prose.^[65] Overall, writers should weigh these trade-offs, testing revisions for natural flow to ensure the avoidance enhances rather than hinders communication.^[11]

Contexts for Acceptable Use

Split infinitives are considered acceptable in contexts where they provide necessary emphasis on the modifying adverb, ensuring the adverb strongly attaches to the verb rather than adjacent elements. For instance, in the phrase "to really understand the concept," the adverb "really" intensifies the verb "understand" directly, avoiding awkward alternatives like "to understand the concept really," which could imply emphasis on the object instead. This usage enhances rhetorical force and precision, as endorsed by modern grammar authorities who prioritize clarity over rigid form.^[5] Similarly, focusing adverbs such as "just" or "even" often require splitting to convey intended stress, with corpus data showing their frequency in split constructions rising significantly in contemporary English.^[27] In spoken language and poetic forms, split infinitives contribute to natural rhythm and idiomatic flow, making them preferable when alternatives disrupt the cadence. Phrases like "to boldly go where no one has gone before" exemplify this, where the split creates a memorable, emphatic beat that aligns with oral delivery or verse structure. Linguistic analyses confirm that such splits preserve the intuitive sound of English in informal speech, where prescriptivist avoidance can result in stilted phrasing.^[5] Usage manuals further support this for contexts demanding eloquence, noting splits as a tool to maintain rhythmic integrity without sacrificing meaning.^[27] Split infinitives also serve to avoid ambiguity by clearly scoping the adverb to the infinitive verb, particularly in complex sentences. Consider "to better prepare students for the exam," where splitting ensures "better" modifies "prepare" rather than the broader clause, preventing misreadings like enhancing preparation indirectly. This clarifying function is highlighted in editorial guidelines and corpus studies.^[5] In 2020s digital contexts, such as social media platforms, split infinitives aid conciseness and naturalness in character-limited posts, reflecting informal online norms. Analysis of Twitter corpora reveals splits comprising over 55% of modified infinitives in Philippine English tweets from 2010-2021, often with adverbs like "actually" or "really" to fit succinct, engaging styles (e.g., "to actually try this hack"). This trend underscores their utility in fast-paced digital communication, where brevity enhances readability without formal constraints.^[66] Overall usage in modern corpora has surged to 97 instances per million words by the 2000s, supporting their role in concise online expression.^[27]