Definition of phoneme

Every language has a limited number of sound types which are shared by all the speakers of the language and are linguistically important because they distinguish words in language. In English there are 20 vowel phonemes and 24 consonant phonemes.

The founder of the phoneme theory was I.A. Baudouin de Courteney, the Russian scientist of Polish origin. His theory of phoneme was developed and perfected by L.V. Shcherba - the head of the Leningrad linguistic school, who stated that in actual speech we utter much greater variety of sounds than we are aware of, and that in every language these sounds are united in a comparatively small number of sound types, which are capable of distinguishing the meaning and the form of words; that is they serve the purpose of social inter communication.

All the actual speech sounds are allophones (or variants) of the phonemes that exist in the language. Those that distinguish words, when opposed to one another in the same phonetic position, are realizations of different phonemes.

Those sounds that cannot distinguish words in a definite language and occur only in central positions or in combination with certain sounds are realizations of one and the same phoneme, its allophones (or variants).

Therefore, the phoneme may be defined as the smallest linguistically relevant unit of the sound structure of a given language which serves to distinguish one word from another.

Allophones (or variants) of a certain phoneme are speech sounds which are realizations of one and the same phoneme and which, therefore, cannot distinguish words. Their articulatory and acoustic distinctions are conditioned by their position and their phonetic environment.

Academician L. V. Shcherba was the first to define the phoneme as a real, independent distinctive unit which manifest itself in the form of allophones. According to him, the phoneme may be viewed as a functional, material and abstract unit. Prof. V.A. Vassilyev developed Shcherba’s theory and presented a detailed definition of the phoneme in his book “English Phonetics. A Theoretical Course”, where he writes that a phoneme is a dialectical unity of three aspects: (1) material, real and objective, (2) abstractional and generalized, (3) functional.

On the one hand, the phoneme is an abstraction and a generalization. It is abstracted from its variants that exist in actual speech and is characterized by features that are common to all its variants (e.g. /b/ is an occlusive, bilabial, lenis consonant, as these features are common to all its allophones).

On the other hand, the phoneme is material, real and objective, because in speech it is represented by concrete material sounds. In other words, the phoneme exists in speech in the material form of speech sounds.

The phoneme correlates with its allophones as the universal correlates with the individual.

Finally, the phoneme is a functional unit because it has certain linguistic functions.