flexions

Flexions, also called inflections, are the set of word forms a lexeme can take to express grammatical information. They encode features such as number, case, gender, tense, aspect, mood, voice, and person, allowing words to fit syntactic roles and agree with other words in a sentence. The same lemma thus appears in several flexions, each with a distinct form.

Flexions arise through several mechanisms. Affixation adds prefixes or suffixes; internal stem changes, such as vowel alternations (ablaut), modify the base form; and sometimes entirely different roots are used (suppletion). Languages vary in their reliance on inflection: synthetic or fusional languages use many inflections, while analytic languages rely more on auxiliary words and word order.

Nouns and adjectives often show agreement inflections, while verbs carry systems of tense, aspect, mood, voice, and subject or object agreement. Pronouns and numerals may also inflect. In some languages, case markings indicate grammatical roles such as subject or possession; in others, these roles are inferred from syntax and context.

Examples help illustrate the idea without extensive tables. In English, the verb walk has inflected forms such as walks (third-person singular present), walked (past tense and past participle), and walking (present participle). In highly inflected languages such as Russian or Latin, a noun or verb can have many distinct forms, each signaling case, number, tense, or other grammatical categories.

Flexions are a central aspect of morphology and crucial for understanding how languages encode grammatical relationships. See also inflection, morphology, and grammar.