Word classes

Abstract The assignment of words into word classes is crucial to analyses of lexical conversion, and to grammatical analysis more generally. Word classes are theoretically based on morphosyntactic distribution, but in practice this does not yield a neat distinction between nouns, verbs, and adjectives. In some languages, there is systematic flexibility in how lexemes appear in morphosyntactic contexts, which can be likened to an extreme degree of lexical conversion. Given these complications, this chapter turns to semantics and pragmatics, highlighting their relevance for a theory of word classes. Conversion involves redeployment of a lexeme from one context into another, and this can be understood as a pragmatic process that maintains semantic content while modulating information structure. This may account for cases where word classes deviate from semantic classes, and explain why some word classes are more semantically coherent than others.