Word stem

In linguistics, a stem is a part of a word. The term is used with slightly different meanings.

In one usage, a stem is a form to which affixes can be attached. Thus, in this usage, the English word friendships contains the stem friend, to which the derivational suffix -ship is attached to form a new stem friendship, to which the inflectional suffix -s is attached. In a variant of this usage, the root of the word (in the example, friend) is not counted as a stem.

In a slightly different usage, which is adopted in the remainder of this article, a word has a single stem, namely the part of the word that is common to all its inflected variants. Thus, in this usage, all derivational affixes are part of the stem. For example, the stem of friendships is friendship, to which the inflectional suffix -s is attached.

Stems may be a root, e.g. run, or they may be morphologically complex, as in compound words (e.g. the compound nouns meat ball or bottle opener) or words with derivational morphemes (e.g. the derived verbs black-en or standard-ize). Hence, the stem of the complex English noun photographer is photo·graph·er, but not photo. For another example, the root of the English verb form destabilized is stabil-, a form of stable that does not occur alone; the stem is de·stabil·ize, which includes the derivational affixes de- and -ize, but not the inflectional past tense suffix -(e)d. That is, a stem is that part of a word that inflectional affixes attach to.

The exact use of the word 'stem' depends on the morphology of the language in question. In Athabaskan linguistics, for example, a verb stem is a root that cannot appear on its own, and that carries the tone of the word. Athabaskan verbs typically have two stems in this analysis, each preceded by prefixes.

Uncovering and analyzing cognation between stems and roots within and across languages has allowed comparative philology and comparative linguistics to determine the history of languages and language families.

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