PHONEME. In PHONETICS and LINGUISTICS, the basic theoretical unit of distinctive sound in the description of SPEECH, out of which syllables are formed, such as the three units /b, I, t/ (consonant, vowel, consonant) in /bit/ (bit). The OED (1989) defines the phoneme as ‘A phonological unit of language that cannot be analysed into smaller linear units and that in any particular language is realized in non-contrastive variants’. The Longman Dictionary of Applied Linguistics (1985) defines the phoneme as ‘the smallest unit of sound in a language which can distinguish two words’, giving the examples pan and ban, that differ only in the contrast of the phonemic consonants /p/ and /b/, and ban and bin, that differ only in the phonemic vowels /æ/ and /I/. The number of phonemes varies from language to language, and from variety to variety within a language. Any such number, as for example the 24 consonants and 20 vowels of RP, are known as a phoneme inventory. A PHONE is a realization in sound of a phoneme, and an allophone is one such realization among others: for example, English /n/ is normally alveolar, but is dental before the dental fricative /ɵ/ in tenth [tɛnɵ]. There are no minimal pairs contrasting dental and alveolar [n], and so the difference is not phonemic: because of this, the two forms are said to be allophones of the same phoneme /n/. When allophones occur in different environments, only one over occurring in one environment, they are said to be in complementary distribution. The term allophone is also used to include the free variant, a sound that can be substituted for another without bringing about a change of meaning. Examples include the various r-sounds of English and the use of the GLOTTAL STOP as a variant of [t] in a word like water. See BLOOMFIELD, -EME, MINIMAL PAIR.

pho·neme / ˈfōnēm/ • n. Phonet. any of the perceptually distinct units of sound in a specified language that distinguish one word from another, for example p, b, d, and t in the English words pad, pat, bad, and bat. Compare with allophone.DERIVATIVES: pho·ne·mic / fəˈnēmik; fō-/ adj.pho·ne·mics / fəˈnēmiks; fō-/ n.

phoneme A small element of real speech that is linguistically significant. The transitions between phonemes are acoustically but not linguistically significant. Phonemes may be used by means of concatenation to produce artificial speech. The particular problem with phoneme concatenation is how to actually perform the join since fluent speech requires fluent transitions. Diphones are the elements of speech between the centers of adjacent phonemes; they include the transitions, and are more useful for speech synthesis.

phoneme Minimum unit of significant sound; a speech sound distinguishing meaning. The phonemes /p/ and /b/ distinguish ‘tap’ from ‘tab’.

phoneme XIX. — F. phonème — Gr. phṓnēma, f. phōneîn speak.