Forminflection

Forminflection is the process by which a word form is altered to express grammatical information about a lexeme. It covers changes in form that signal features such as tense, number, case, gender, mood, and person. In many languages, a single lemma has a set of inflected forms arranged in paradigms or conjugations that map to different grammatical contexts.

Forms can be realized in several ways. Affixation uses prefixes, suffixes, or infixes to mark grammatical information. Stem changes or internal modifications, such as vowel alternations, can also signal inflection. Suppletion occurs when entirely different words are used to express related forms. Inflectional changes are distinguished from derivational changes, which create new words or shift a word to a new part of speech rather than merely marking grammar. Inflection can be productive and regular, or irregular and unpredictable.

Inflection systems vary widely across languages. Some languages have rich inflection with many cases, tenses, moods, and agreement markers (examples include Finnish, Russian, Latin). Others are more analytic, using word order and auxiliary words rather than extensive inflection (for instance, Mandarin Chinese). Even within a language, different word classes may show different degrees of inflection: nouns and adjectives often mark number and case, while verbs encode tense, aspect, mood, and agreement.

In linguistics and natural language processing, forminflection is essential for understanding and generating language. Analyses identify lemmas, inflectional affixes, and the full set of inflected forms; generation involves applying appropriate inflectional rules to produce correct forms in context. Morphophonological rules and resources like whitelisted paradigms or finite-state models are commonly used to handle inflectional variation and irregularities.