suppletus

Suppletus is a Latin adjective meaning supplied, furnished, or provided. In linguistic writing, the related concept is suppletion, which describes a pattern in which different inflected forms of a word are derived from distinct historical roots rather than a single, shared stem. The Latin form suppletus itself is not commonly used in contemporary English analyses, but it underpins the terminology of suppletive morphology.

Suppletion occurs when a paradigm is incomplete or irregular because some forms come from a different root. This is different from regular irregularities produced by predictable sound changes within the same root. In practice, a suppletive paradigm may replace an expected inflected form with a form that comes from another word entirely. The most frequently cited example in English is the forms of the verb to be: am, is, are in the present tense, and was, were in the past tense, which come from different historical roots rather than from a single stem.

Common examples and discussions of suppletion cover various languages and verb classes, with be being the classic teaching instance in English. Suppletion also appears in other languages, including some Romance and Slavic languages, as well as in theoretically analyzed cases across the world, where entire paradigms or key inflected forms are supplied by different roots.

See also: suppletion, suppletive forms, irregular verbs, morphological irregularities, Latin grammar.