PHONEME
The basic building block of any discussion of articulatory phonetics is phoneme. The technical term phoneme is usually used to refer to sound segments. Linguists define phoneme as the minimal unit of sound (or sometimes syntax). The study of phonemes is the study of the sounds of speech in their primary function, which is to make vocal signs that refer to the fact that different things sound different. The phonemes of a particular language are those minimal distinct units of sound that can distinguish meaning in that language. In English, the /p/ sound is a phoneme because it is the smallest unit of sound that can make a difference of meaning if, for example, it replaces the initial sound of such words as bill, till, or dill, making the word pill. The vowel sound /ɪ/ of pill is also a phoneme because its distinctness in sound makes pill, which means one thing, sound different from pal, which means another. Two different sounds, reflecting distinct articulatory activities, may represent two phonemes in one language but only a single phoneme in another. Thus phonetic /r/ and /l/ are distinct phonemes in English, whereas these sounds represent a single phoneme in Japanese, just as [ph] and [p] in pie and spy, respectively, represent a single phoneme in English although these sounds are phonetically distinct.
Phonemes are not letters; they refer to the sound of a spoken utterance. For example, flocks and phlox have exactly the same five phonemes. Similarly, bill and Bill are identical phonemically, regardless of the difference in meaning. Each language has its own inventory of phonetic differences that it treats as phonemic (that is, as necessary to distinguish meaning). For practical purposes, the total number of phonemes for a language is the least number of different symbols adequate to make an unambiguous graphic representation of its speech that any native speaker could read if given a sound value for each symbol, and that any foreigner could pronounce correctly if given additional rules covering nondistinctive phonetic variations that the native speaker makes automatically. For convenience, each phoneme of any language may be given a symbol.
