Suppletion

In linguistics and etymology, suppletion is traditionally understood as the use of one word as the inflected form of another word when the two words are not cognate. For those learning a language, suppletive forms will be seen as "irregular" or even "highly irregular". The term "suppletion" implies that a gap in the paradigm was filled by a form "supplied" by a different paradigm. Instances of suppletion are overwhelmingly restricted to the most commonly used lexical items in a language.

An irregular paradigm is one in which the derived forms of a word cannot be deduced by simple rules from the base form. For example, someone who knows only a little English can deduce that the plural of girl is girls but cannot deduce that the plural of man is men. Language learners are often most aware of irregular verbs, but any part of speech with inflections can be irregular. For most synchronic purposes — first-language acquisition studies, psycholinguistics, language-teaching theory — it suffices to note that these forms are irregular. However, historical linguistics seeks to explain how they came to be so and distinguishes different kinds of irregularity according to their origins. Most irregular paradigms (like man:men) can be explained by philological developments that affected one form of a word but not another (in this case, Germanic umlaut). In other cases, the historical antecedents of the current forms once constituted a regular paradigm. Historical linguists adopted the term "suppletion" to distinguish irregularities like person:people or cow:cattle that cannot be so explained because the parts of the paradigm have not evolved out of a single form.

Suppletion exists in more than 71 languages around the world. These languages are from various language families : Indo-Aryan, Dravidian, Arabic, Romance, etc. For example, in Georgian, the paradigm for the verb "to come" is composed of four different roots (di- / -val- / -vid- / -sul-). Similarly, in Modern Standard Arabic, the verb jāʾ "come" usually uses the form taʿāl for its imperative, and the plural of marʾah "woman" is nisāʾ. Nonetheless, some of the more archaic Indo-European languages are particularly known for suppletion. Ancient Greek, for example, has some 20 verbs with suppletive paradigms, many with 3 separate roots. (See Ancient Greek verbs § Suppletive verbs.)

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