Most common words in English
The most common words in English refer to the lexical items that occur with the highest frequency in written and spoken language, as quantified through analyses of large-scale linguistic corpora representing contemporary usage. These words are overwhelmingly function words—such as articles, prepositions, pronouns, auxiliary verbs, and conjunctions—that serve structural roles rather than conveying specific content, enabling efficient communication across diverse contexts. For instance, in the Corpus of Contemporary American English (COCA), a balanced collection of over 1 billion words from texts dated 1990 to 2019 spanning fiction, news, academic writing, and spoken transcripts, the top 100 words account for nearly half of all tokens in the corpus, underscoring their dominance in everyday English.[1][2] Key examples from COCA illustrate this pattern: the article the ranks first, followed by the verb be (encompassing forms like is, are, and was), the conjunction and, the preposition of, and the indefinite article a, each among the most frequent words in the corpus. The full top ten includes in, to (as infinitive marker and preposition), have, it, and that, which together represent core elements of syntax and basic reference. This distribution aligns with Zipf's law, a principle in linguistics stating that word frequency is inversely proportional to its rank (e.g., the second-most common word appears roughly half as often as the first), a pattern observed across languages and confirmed in English corpora like COCA.[1][3] Understanding these frequencies is crucial for fields like natural language processing, where they inform algorithms for text prediction and compression, and for second-language acquisition, as mastering the top 1,000–2,000 word families provides 80–90% coverage of typical texts, reducing comprehension barriers. Variations exist between spoken and written English—spoken corpora emphasize pronouns like you and I more heavily—while differences between American and British English are minimal for high-frequency items. COCA, last significantly updated in 2019 to over 1 billion words, continues to refine these rankings, reflecting usage in digital media and global contexts up to that point.[4][5]Determination Methods
Corpus Selection
A corpus is a large, structured collection of authentic texts or transcribed speech that captures natural language use, serving as the foundational dataset for empirical linguistic studies such as word frequency analysis.[6] These collections are typically stored electronically and designed to be principled, meaning they adhere to explicit sampling methods to ensure reliability and applicability to broader language patterns.[7] Selecting an appropriate corpus requires careful consideration of several key criteria to achieve representativeness of English usage. Size is paramount, with corpora often encompassing millions to billions of words to provide sufficient data for detecting patterns in both high- and low-frequency items; for instance, smaller corpora around 100 million words suffice for general queries, while larger ones exceeding 1 billion enable detailed subanalyses.[8] Diversity ensures inclusion of varied text types, such as spoken dialogues, written fiction, news articles, and academic prose, reflecting the multifaceted ways English is employed across contexts.[7] Balance addresses proportional representation of language varieties, including differences between British and American English, as well as demographic factors like age and region, to minimize distortions in frequency estimates.[8] Major corpora exemplify these principles in practice. The British National Corpus (BNC), compiled in the 1990s, totals 100 million words with 90% written material from genres like newspapers, books, and essays, and 10% spoken content from conversations and broadcasts, aiming to mirror late-20th-century British English.[9] The Corpus of Contemporary American English (COCA) spans over 1 billion words from 1990 to 2019, evenly distributed across eight genres—including spoken transcripts, fiction, popular magazines, newspapers, and academic journals—to offer a balanced view of modern American English.[5] In contrast, the Google Books Ngram corpus aggregates trillions of words from digitized books dating from the 1500s to 2019, subdivided into subsets like American English (155 billion words) and English Fiction, providing extensive diachronic coverage though primarily from published written sources.[10][11] Despite these strengths, corpus selection presents notable challenges. Historical corpora like Google Books Ngram incorporate archaic language from earlier centuries, potentially inflating frequencies of obsolete terms irrelevant to contemporary English.[12] Dialectal variations, such as regional idioms in non-standard Englishes, are often underrepresented, leading to skewed results favoring standard varieties like British or American norms.[8] Additionally, source biases—such as the overrepresentation of formal, published writing in book-heavy corpora—can undervalue informal spoken or digital language, compromising overall representativeness.[7]Frequency Calculation Techniques
The calculation of word frequencies in English begins with preprocessing the corpus text to ensure consistent and meaningful analysis. Tokenization is the foundational step, involving the segmentation of continuous text into discrete tokens, usually words, by identifying boundaries such as spaces, punctuation, or hyphens. This process must handle challenges like possessives (e.g., "John's") or hyphenated terms to avoid splitting meaningful units inappropriately. Following tokenization, lemmatization reduces inflected or variant forms of words (such as "running," "runs," and "ran") to their base or dictionary form, known as the lemma, using morphological analysis often supported by dictionaries or rule-based systems. This step is crucial for aggregating frequencies across related forms, preventing inflated counts for inflections that do not represent distinct lexical items. Once tokenized and lemmatized, occurrences of each token are counted to produce raw frequency tallies, which form the basis for ranking words by commonality. Normalization techniques are applied to these raw counts to account for variations in corpus size and enable cross-corpus comparisons. A common method is expressing frequencies as words per million (WPM), calculated by dividing the raw count by the total number of tokens in the corpus and multiplying by one million; this standardizes results regardless of whether the corpus contains 1 million or 1 billion words.[13] Relative frequency, as a proportion of total tokens, offers another normalized measure, particularly useful for probabilistic modeling in linguistics.[14] Decisions on handling inflections, contractions, and multi-word units significantly influence frequency outcomes. While lemmatization addresses inflections by grouping variants, contractions like "don't" are typically treated as single tokens to reflect their unitary usage in natural language, though some analyses may expand them for lemma-level counting. Multi-word units, such as compounds ("ice cream") or fixed phrases, pose challenges; they may be counted as separate words in basic tokenization or preserved as single entries using n-gram methods or association measures like mutual information to capture idiomatic expressions without fragmenting their semantic integrity.[15] Statistical measures extend beyond raw or normalized counts to model distributional patterns. Raw frequency simply tallies appearances, but relative frequency provides a proportional view, highlighting a word's prominence within the corpus. A key principle governing these distributions is Zipf's law, which posits that word frequency is inversely proportional to its rank in the frequency list. Formally, the frequency f(r) of the word at rank r approximates f(r) \approx \frac{c}{r^s}, where c is a constant and s \approx 1 for English, implying the most common word (rank 1) appears roughly twice as often as the second-ranked word. This power-law relationship, observed across large corpora, underscores the skewed nature of English vocabulary usage, with a small set of words accounting for the majority of occurrences. Various software tools facilitate these techniques for researchers. AntConc, a free corpus analysis application, supports tokenization, lemmatization via external plugins, frequency counting, and normalization through its word list and collocate functions, making it accessible for detailed concordancing and statistical output.[16] Sketch Engine, a web-based platform, automates advanced frequency calculations including lemma-based lists, n-gram handling for multi-word units, and normalized metrics like WPM, often integrated with large-scale corpora for efficient processing.[17]Primary Word Lists
Top 100 Words
The top 100 most frequent words in English, derived from analyses of large-scale corpora like the Oxford English Corpus (OEC), a billion-word database of contemporary written English, dominate usage in texts and account for roughly 50% of all word occurrences.[18] This high coverage underscores their foundational role in sentence structure, with function words such as articles, prepositions, pronouns, and auxiliary verbs comprising the majority.[18] The following table enumerates the top 100 words based on OEC frequency rankings, including their primary part of speech for contextual understanding. Frequencies vary slightly by corpus but follow a steep Zipfian distribution, where the first word ("the") appears over 100 times more often than the 100th.[18]| Rank | Word | Part of Speech |
|---|---|---|
| 1 | the | Article |
| 2 | be | Verb |
| 3 | to | Preposition |
| 4 | of | Preposition |
| 5 | and | Conjunction |
| 6 | a | Article |
| 7 | in | Preposition |
| 8 | that | Pronoun |
| 9 | have | Verb |
| 10 | I | Pronoun |
| 11 | it | Pronoun |
| 12 | for | Preposition |
| 13 | not | Adverb |
| 14 | on | Preposition |
| 15 | with | Preposition |
| 16 | he | Pronoun |
| 17 | as | Preposition |
| 18 | you | Pronoun |
| 19 | do | Verb |
| 20 | at | Preposition |
| 21 | this | Determiner |
| 22 | but | Conjunction |
| 23 | his | Pronoun |
| 24 | by | Preposition |
| 25 | from | Preposition |
| 26 | they | Pronoun |
| 27 | she | Pronoun |
| 28 | or | Conjunction |
| 29 | an | Article |
| 30 | will | Verb |
| 31 | my | Pronoun |
| 32 | one | Number |
| 33 | all | Determiner |
| 34 | would | Verb |
| 35 | there | Adverb |
| 36 | their | Pronoun |
| 37 | what | Pronoun |
| 38 | so | Adverb |
| 39 | up | Adverb |
| 40 | out | Adverb |
| 41 | if | Conjunction |
| 42 | about | Preposition |
| 43 | who | Pronoun |
| 44 | get | Verb |
| 45 | which | Pronoun |
| 46 | go | Verb |
| 47 | me | Pronoun |
| 48 | when | Adverb |
| 49 | make | Verb |
| 50 | can | Verb |
| 51 | like | Preposition |
| 52 | time | Noun |
| 53 | no | Determiner |
| 54 | just | Adverb |
| 55 | him | Pronoun |
| 56 | know | Verb |
| 57 | take | Verb |
| 58 | people | Noun |
| 59 | into | Preposition |
| 60 | year | Noun |
| 61 | your | Pronoun |
| 62 | good | Adjective |
| 63 | some | Determiner |
| 64 | could | Verb |
| 65 | them | Pronoun |
| 66 | see | Verb |
| 67 | other | Determiner |
| 68 | than | Conjunction |
| 69 | then | Adverb |
| 70 | now | Adverb |
| 71 | look | Verb |
| 72 | only | Adverb |
| 73 | come | Verb |
| 74 | its | Pronoun |
| 75 | over | Preposition |
| 76 | think | Verb |
| 77 | also | Adverb |
| 78 | back | Adverb |
| 79 | after | Preposition |
| 80 | use | Verb |
| 81 | two | Number |
| 82 | how | Adverb |
| 83 | our | Pronoun |
| 84 | work | Verb |
| 85 | first | Adjective |
| 86 | well | Adverb |
| 87 | way | Noun |
| 88 | even | Adverb |
| 89 | new | Adjective |
| 90 | want | Verb |
| 91 | because | Conjunction |
| 92 | any | Determiner |
| 93 | these | Determiner |
| 94 | give | Verb |
| 95 | day | Noun |
| 96 | most | Determiner |
| 97 | us | Pronoun |
| 98 | her | Pronoun |
| 99 | than | Conjunction |
| 100 | water | Noun |
Extended Lists Beyond 100
As frequency lists extend beyond the top 100 words, which are predominantly function words like articles and pronouns, the vocabulary shifts toward content words that convey specific ideas, actions, and entities central to everyday communication. In the range of ranks 101 to 500, this transition is evident with the inclusion of common nouns and verbs; for example, in the New General Service List (NGSL), developed by Browne, Culligan, and Phillips based on a 273-million-word corpus of contemporary English, words such as "need" (rank 101), "child" (rank 114), "life" (rank 126), "place" (rank 130), and "change" (rank 131) emerge, reflecting a move from grammatical essentials to descriptive and relational terms.[20] These words often appear in narrative and descriptive contexts, bridging basic syntax with thematic content. Further into the 501 to 1000 range, word frequencies reveal greater specificity, incorporating verbs and nouns tied to particular activities, objects, and concepts that arise in varied discourse. Drawing from the same NGSL, examples include "practice" (rank 501), "improve" (rank 503), "action" (rank 505), "strong" (rank 506), "economic" (rank 509), "travel" (rank 512), "project" (rank 546), and "search" (rank 950), which denote processes, qualities, and domains like professional or social interactions.[20] This segment highlights vocabulary that supports more nuanced expression, such as specialized actions (e.g., "explain" at rank 539) or entities (e.g., "system" appearing in related forms around this range in corpus analyses). The cumulative coverage provided by the top 1000 words is substantial, accounting for approximately 80% of word occurrences in typical English texts, according to analyses by Nation based on large corpora like the British National Corpus. This high overlap underscores their efficiency for comprehension in general reading and listening, though the remaining 20% draws from rarer, context-specific terms. Prominent lists like the NGSL and the General Service List (GSL), originally compiled by West in 1953 and updated by Bauman and Culligan, provide structured examples of these extended frequencies. The GSL, derived from mid-20th-century corpora, includes transitional words around rank 150 such as "point," "form," and "child," and more specific ones near rank 600 like "employ" and "defence," up to "master" near rank 900.[21] For academic extensions, the Academic Word List (AWL) by Coxhead, based on a 3.5-million-word corpus of university texts, overlaps with this range in written English, featuring words like "approach," "concept," "benefit," "environment," "achieve," and "category" that enhance coverage in formal contexts without dominating general use. To illustrate patterns, the following table excerpts 10 representative words from key ranges in the NGSL:| Rank Range | Sample Words (with Ranks) |
|---|---|
| 101–150 | need (101), much (102), how (103), back (104), child (114), life (126), place (130), change (131), problem (136), great (142) |
| 501–550 | practice (501), improve (503), action (505), strong (506), difficult (510), travel (512), relationship (540), quality (541), project (546), sign (548) |
| 901–950 | quarter (901), central (902), cold (903), object (904), push (907), normal (910), suffer (912), match (915), resource (930), doubt (947) |
Linguistic Analysis
Parts of Speech Breakdown
In analyses of high-frequency English words, certain parts of speech dominate the rankings due to their essential roles in sentence structure and communication. For instance, in the top 100 most frequent words from the British National Corpus (BNC), a 100-million-word collection of late 20th-century British English, function words such as prepositions, pronouns, and determiners account for approximately 60% of the list, while content words like nouns, main verbs, and adjectives comprise the remaining 40%.[22] This distribution highlights how grammatical elements, which form closed-class categories with limited membership, outpace open-class words that can expand indefinitely through new coinages. The BNC data reveals specific proportions across categories: determiners (including articles) hold the highest share at 13%, followed by verbs at 20% (with main verbs at 14% and auxiliaries/modals at 6%), prepositions at 11%, pronouns at 10%, and adverbs at 10%. Conjunctions contribute 6%. In contrast, nouns and adjectives are underrepresented at 6% and 4%, respectively, reflecting their role in conveying specific content rather than universal structure.[22][23]| Part of Speech | Percentage | Top Examples |
|---|---|---|
| Determiner | 13% | the, a, this, that, their |
| Verb (total) | 20% | be, have, do, say, go |
| Preposition | 11% | of, in, to, for, with |
| Pronoun | 10% | it, I, you, he, they |
| Adverb | 10% | not, so, up, just, very |
| Auxiliary/Modal Verb | 6% | will, would, can, could |
| Conjunction | 6% | and, but, or, if, than |
| Noun | 6% | time, year, people, way |
| Adjective | 4% | last, other, new, good |
Function vs. Content Words
In linguistics, words in English are broadly categorized into function words and content words based on their grammatical and semantic roles. Function words, also known as grammatical words, form a closed class of a limited number—approximately 300 in English—and include items like articles ("the"), conjunctions ("and"), prepositions ("to"), pronouns ("it"), and auxiliary verbs ("be"). These words carry low semantic load, primarily serving structural purposes such as indicating relationships between other words or marking grammatical categories, rather than conveying substantive meaning.[24] In contrast, content words, or lexical words, belong to open classes that can expand indefinitely and encompass nouns ("people"), main verbs ("say"), adjectives ("good"), and adverbs ("well"), which provide the core informational content of sentences with high semantic value.[24] A striking frequency disparity exists between these categories in English corpora, where function words overwhelmingly dominate the most common usage due to their essential role in syntax. For instance, in the British National Corpus (BNC), approximately 60% of the top 100 most frequent words are function words, accounting for a disproportionate share of everyday language despite their small total inventory.[22] As frequency lists extend beyond the top 100—such as into the 1,000 to 25,000 range—content words become more prevalent, comprising the majority of entries and reflecting their role in expressing varied ideas.[24] Prominent examples illustrate this divide: among the highest-ranking function words are prepositions like "of" and "in," modals such as "will" and "can," and determiners including "the" and "a," which appear repeatedly to glue sentences together.[22] Content words, while less frequent overall, emerge more prominently in extended lists; for example, nouns like "year," "time," and "people" rank highly but trail behind function words in the top tiers, contributing specific referential meaning.[22][25] This dichotomy ties into broader linguistic theory, particularly syntax, where function words enforce grammatical rules and enable the flexible arrangement of content words, and Zipf's law, which describes the skewed frequency distribution of words in natural language— with function words contributing to the steep initial drop-off in rankings by occupying the highest frequencies.[26] The law posits that word frequency is inversely proportional to rank, a pattern amplified in English by the closed-class nature of function words, which skew the overall distribution toward a small set of high-usage items essential for coherence.[27]Variations and Comparisons
Differences Across Corpora
Word frequency rankings exhibit notable variations depending on the genre represented in the corpus, as spoken and written English prioritize different linguistic features. In spoken corpora such as the Switchboard corpus of American telephone conversations or the spoken subsection of the British National Corpus (BNC), contractions like "'s" (for "is" or "has") rank highly—often in the top 10—due to their prevalence in casual, interactive dialogue, alongside personal pronouns such as "I" and "you" that reflect direct address and first-person narration. Fillers like "uh" or "um" also achieve elevated ranks in purely spoken data, appearing far more frequently than in written texts to mark pauses or hesitation. In contrast, written corpora, particularly those emphasizing news genres in the Corpus of Contemporary American English (COCA), favor content words like "said" and "people," which support narrative reporting and description, while full verb forms such as "is" and "was" outrank their contracted counterparts.[28][5][29] Regional dialects further influence frequency rankings, with American English corpora like COCA diverging from British English ones like the BNC in both vocabulary choices and spelling variants. For instance, the American past participle "gotten" ranks higher in COCA (appearing over 10 times more frequently per million words) compared to the British-preferred "got" in the BNC, reflecting divergent grammatical preferences. Similarly, "color" is more common in American texts, while "colour" dominates in British ones, leading to split rankings for color-related lemmas across corpora. Cultural and topical differences amplify this: words like "baseball" and "congressional" rank within the top 5,000 in COCA but fall outside in the BNC, whereas "football" (referring to soccer) and "Tory" are more prominent in British data.[30][31] The size of a corpus significantly affects the stability of rankings, particularly for lower-frequency words, as smaller datasets amplify sampling variability. In corpora under 20 million words, low-frequency items (e.g., those occurring fewer than 20 times) exhibit unstable ranks due to insufficient token counts, making comparisons unreliable for rare vocabulary. Larger corpora, such as the billion-word COCA or the multi-billion-word Google Books Ngram dataset, provide more robust estimates, revealing consistent long-term trends while minimizing noise in tail-end frequencies. Research indicates that stability improves markedly above 16-30 million words, allowing reliable detection of subtle shifts.[32][33] These differences manifest in rank shifts for specific words across corpora and time periods within large datasets. For example, "computer" ranked outside the top 10,000 in 1980s subsets of historical corpora like the Google Books Ngram (with frequencies around 1-2 per million words), but climbed into the top 1,000 by the 2000s in COCA and similar modern bodies, driven by technological proliferation (reaching 30+ per million). The following table compares top 10 rankings across representative corpora, highlighting genre and regional influences (normalized per million words; lemmas used for COCA's "be," word forms for BNC):| Rank | COCA (Mixed, American, 1990-2019) | BNC Written (British, 1990s) | BNC Spoken (British, 1990s) |
|---|---|---|---|
| 1 | the | the | I |
| 2 | be (incl. forms) | of | you |
| 3 | and | and | the |
| 4 | of | a | and |
| 5 | a | in | to |
| 6 | in | to | a |
| 7 | to | is | it |
| 8 | have | was | that |
| 9 | it | it | of |
| 10 | I | for | 's (contraction) |
Historical Evolution
In Old and Middle English periods prior to 1500, the language featured a high degree of inflection, with common words often appearing in varied forms to indicate grammatical relations such as case, number, and gender.[34] Core vocabulary drew heavily from Anglo-Saxon roots, including demonstratives like "þæt" (meaning "that"), which ranked among the most frequent due to its role in pointing to nouns or clauses in synthetic sentence structures.[35] Other prevalent items encompassed pronouns such as "ic" (I) and "hē" (he), and verbs like "wæs" (was), reflecting a grammar reliant on endings rather than fixed word order.[36] The Helsinki Corpus of English Texts, spanning from the 8th to the 18th century, illustrates this through samples where inflected forms dominate, comprising up to 1.5 million words of diachronic data.[37] During the Early Modern English era (1500–1800), function words like articles and prepositions began to stabilize in frequency and form, coinciding with the Great Vowel Shift, a series of pronunciation changes that elevated long vowels and contributed to the divergence between spoken and written English.[38] This shift, occurring roughly between the 15th and 18th centuries, indirectly supported standardization by freezing spellings in print before sounds fully evolved. Simultaneously, language contact from the Renaissance introduced borrowings from French and Latin, elevating words such as "people" in usage as scholarly and administrative texts proliferated.[39] The printing press, introduced by William Caxton in 1476, accelerated this by homogenizing regional dialects and promoting the London variety, thus fixing common words in consistent orthography across printed works.[40] From the 19th to 20th centuries, industrialization reshaped lexical priorities, propelling nouns related to labor and temporality into higher frequencies; for instance, "work" and "time" ascended in printed texts amid discussions of factory production and mechanized schedules.[41] In the 21st century, digital influences have further altered rankings, with terms like "information" surging due to data proliferation in online media and "online" entering the top 1000 words in contemporary corpora as internet usage normalized.[42] The Corpus of Contemporary American English (COCA), covering 1990–present, shows "information" among the top 500 lemmas, reflecting technological discourse.[5] Historical corpora provide quantitative evidence of these shifts; the Google Books Ngram dataset, analyzing billions of words from printed books since 1500, reveals "the" maintaining relative consistency from the 1700s onward as a stable function word, while content nouns like "government" exhibited a marked surge post-1800, peaking in the mid-19th century amid political expansions.[43] This dataset, derived from a large sample of published books up to 2019 (version 3, released 2020), underscores a transition to greater lexical stability by the 19th century, with top words retaining rankings longer than in earlier periods.[43][10] In the 2020s, global events such as the COVID-19 pandemic and advancements in artificial intelligence have influenced word frequencies, with terms like "pandemic" and "AI" showing marked increases in recent analyses of updated corpora like Google Books Ngram extensions and ongoing digital collections. As of 2025, these shifts highlight the continued impact of health crises and technology on everyday language.[10] These evolutions stem from interconnected factors: language contact through conquests and trade introduced loanwords, standardization via the printing press unified variants, and societal changes like industrialization and digitalization prioritized new semantic domains in everyday and formal usage.[39][40][41]Practical Applications
In Language Education
In language education, particularly for English as a second language (ESL) learners, vocabulary acquisition strategies emphasize prioritizing high-frequency words to maximize comprehension efficiency. Educators often focus on the most common 2,000 word families, which account for approximately 80% of occurrences in everyday English texts, allowing learners to engage with authentic materials early in their studies.[44] This approach enables rapid progress in reading and writing by building a foundational lexicon that supports contextual guessing for less frequent terms. Key resources for implementing these strategies include established word lists integrated into ESL curricula. The General Service List (GSL), comprising about 2,000 high-frequency words, serves as a core component in many programs, such as those at Troy University, where learners master the first 1,200 GSL words to develop spelling and usage proficiency.[45] Similarly, modern language learning apps like Duolingo and Babbel incorporate high-frequency vocabulary into gamified lessons to reinforce retention through repetition and contextual practice.[46] Pedagogically, teaching function words—such as articles ("the"), prepositions ("of"), and conjunctions ("and")—before delving deeply into content words fosters faster fluency by establishing sentence rhythm and grammatical structure. Lesson plans often begin with these elements through interactive activities like rhythm drills and games, which improve pronunciation accuracy and overall intelligibility for learners from syllable-timed language backgrounds.[47] Research by Paul Nation supports this prioritization, demonstrating that mastery of the top 3,000 word families enables about 95% comprehension of typical texts, sufficient for independent reading in graded materials.[48] However, challenges arise from cultural biases embedded in the corpora used to compile these frequency lists, which often draw from Western, English-dominant sources like British or American texts, potentially marginalizing global varieties of English in ESL instruction. This can lead to skewed representations that overlook non-native speaker contexts, complicating equitable teaching for diverse learners worldwide.[49]In Computational Linguistics
In computational linguistics, the most common words in English, often function words like "the," "and," and "of," play a pivotal role in preprocessing tasks such as stopword removal, which excludes high-frequency, low-information terms to enhance efficiency in information retrieval (IR) and text analysis. This technique reduces noise in corpora, saving processing time and memory while preserving retrieval effectiveness, as demonstrated in studies on English text documents where stopword elimination maintains or improves IR performance without significant loss of semantic content.[50][51] Language models leverage word frequency distributions from large corpora to prioritize training data and evaluate performance. For instance, BERT's vocabulary of 30,000 WordPiece tokens is constructed from frequency-based subword tokenization on corpora like BooksCorpus (800 million words) and English Wikipedia (2.5 billion words), enabling the model to handle common words effectively through masked language modeling where 15% of tokens, including frequent ones, are predicted bidirectionally. Perplexity, a key metric for assessing language model quality, measures prediction uncertainty on sequences and is inherently lower for common words due to their predictability in context, as seen in evaluations where models like GPT-2 achieve perplexity scores around 16-19 on WikiText-2 by better handling frequent n-grams.[52][53] Practical applications of common word frequencies include spell-checkers and auto-completion systems, which rank suggestions based on usage probabilities to prioritize corrections for high-frequency terms. In medical IR, frequency-based re-sorting of spell-check outputs from query logs increases the accuracy of top-ranked suggestions by 63%, outperforming standard tools like ASpell. Similarly, auto-completion in search interfaces predicts common words like "the" as next tokens using frequency-weighted n-gram models. In sentiment analysis, term weighting schemes incorporate frequencies via metrics like TF-IDF or BM25 to emphasize discriminative high-frequency words, yielding improvements such as 4.21% in F-measure on opinion extraction tasks.[54][55] Libraries like NLTK and spaCy provide built-in frequency-derived stopword lists for English, facilitating these applications. NLTK's stopwords corpus, sourced from Porter et al. and containing 179 English terms, filters low-content words in tasks like text classification, where non-stopwords comprise about 73% of Reuters corpus content. SpaCy's English stop words, defined in language data files as high-frequency terms (e.g., approximately 305 entries including "and" and "I"), enable efficient token filtering via theToken.is_stop attribute. Search engines like Google incorporate common word frequencies in query processing and auto-suggestions, adjusting for typical spellings and ignoring capitalization to match user intent with prevalent terms.[56][57][58]
Advancements in multilingual NLP extend English word frequency proxies to low-resource languages, where proxy models trained on English-centric data predict performance for tasks like machine translation across 56 languages. Frameworks like ProxyLM use smaller English-based surrogates to estimate larger multilingual models' capabilities, achieving up to 37× speedup and lower error rates by leveraging frequency patterns as transferable priors for underrepresented languages.[59]