morphophoneme (n.)

The basic unit recognized in a MORPHOPHONEMIC LEVEL of analysis. It is usually symbolized by the use of a capital letter within brace BRACKETS, e.g. {F}, {T}. One of the original examples used in order to justify establishing this entity was the ALTERNATION between /f/ and /v/ in some English plurals, such as knife ~ knives. There is no predictable alternation between /f/ and /v/ for English WORDS in general, but only in this specific GRAMMATICAL CONTEXT. This fact, it is argued, can be captured by setting up a morphophoneme {F}, as in {naIF}: in a singular context this is realized as /f/, in a plural context as /v/. Each morphophonemic symbol thus represents the class of PHONEMES which occurs within a particular set of grammatical ENVIRONMENTS. In later linguistic theory, the term SYSTEMATIC PHONEME is more widespread.