morphophoneme

The term morphophoneme refers to an abstract unit in the phonology of a language that merges features of both a morpheme and a phoneme. It is used when a morpheme’s pronunciation varies according to phonological context but the variations are systematic and merge in meaning with a single underlying phoneme. Morphophoneme analysis explains why a single lexical item can appear with different surface forms while maintaining a single grammatical meaning.

Unlike a regular morpheme, which has a fixed meaning, morphophonemes can have multiple phonetic realizations that are conditioned by surrounding sounds. For instance, the plural morpheme in English appears as /s/, /z/, or /ɪz/ after nouns with different final sounds, yet all forms represent the same grammatical number. Similarly, the past‑tense morpheme in Spanish may be realized as /t/ or /d/ depending on the preceding consonant. In these cases, the morpheme is analyzed as a single morphophoneme with phonological rules that determine its surface variants.

The concept assists linguists in reducing the number of explicit morphemes in a language by treating phonetic alternations as part of a single morphological entry. Morphophoneme analysis is common in languages with complex agreement systems, clitic attachment, or vowel harmony, where surface shapes frequently shift. It bridges morphology and phonology, allowing a single lexical entry to account for multiple forms that vary predictably in a language’s sound system.