Vocabularies

Vocabularies are the inventories of words that make up the lexicon of a language or of an individual speaker. In linguistic usage, the term lexicon is often used to denote the full set of lexical units—words and fixed expressions—that a person recognizes and can use. A distinction is commonly made between active (productive) vocabulary, consisting of words a person readily uses in speech and writing, and receptive (passive) vocabulary, consisting of words recognized and understood in listening or reading but not necessarily produced.

For a language community, vocabulary size and structure reflect its history, domain specialization, and ongoing change. Individual vocabularies vary widely by age, education, occupation, and exposure. Estimates for adult native speakers place active vocabularies roughly in the range of a few tens of thousands of words, with passive vocabularies larger still; counts are highly language-specific and method-dependent. Vocabulary development occurs throughout life, driven by reading, listening, schooling, and deliberate study, and is shaped by semantic relationships, word formation, and frequency of use. Multilingual speakers maintain separate vocabularies for each language and may share or transfer knowledge between them.

Vocabularies can be organized in different ways. Alphabetical lists are common in dictionaries, while semantic-field groupings or word-family relations (derivations, cognates) aid learning and analysis. In lexicography, entries are defined by lemmas and expanded with inflected forms and multiword expressions.

In computational linguistics and natural language processing, a model’s vocabulary is the set of tokens it can recognize or generate. Vocabulary size affects coverage and handling of unseen words, leading to techniques such as subword modeling (byte-pair encoding, WordPiece, SentencePiece) to manage rare or agglutinated forms.