In Quebec, an allophone is a person whose mother tongue is a language other than French or English. See Allophone (Quebec).

In phonetics, an allophone is one of several similar phones that belong to the same phoneme. A phone is a sound that has a definite shape as a sound wave, while a phoneme is a basic sound that can distinguish words (i.e. changing one phoneme in a word can produce another word); speakers of a particular language perceive a phoneme as a single distinctive sound in that language. Thus an allophone is a phone considered as a member of one phoneme.

Each allophone is used in a specific phonetic context. Not all phonemes have significantly different allophones, but there are always minor differences in articulation from one piece of speech to the next.

For example, p as in pin and p as in spin are allophones for the phoneme p in the English language because they occur in complementary distribution. English speakers generally treat these as the same sound, but they are different. The latter is unaspirated: it sounds a little more like the b of English. This may be noticed by English speakers if they hear the unaspired p without the preceding s. The s is the usual context for the unaspirated allophone.

Chinese treats these two phones differently and the latter is written as b in pinyin; thus, they are not allophones in Chinese.

Similarly, English-speaking people may become aware of the difference between two allophones of the phoneme t when they consider the pronunciations of the following phrases:

night rate

nitrate

See also

• List of phonetics topics