Allofoon

Allofoon is the linguistic term for a phonetic variant of a phoneme that appears in particular phonological environments. In English-language descriptions this variant is usually called an allophone. Allofoon are the concrete realizations of an abstract phoneme; different allophones do not typically create new meanings in a language, even though they may sound different.

Most allophony falls into two main patterns: complementary distribution and free variation. In complementary distribution, the allophones never occur in the same environment, so each environment has a single realization. In free variation, speakers may choose among different allophones in the same environment without changing meaning. Narrow transcription can mark the allophonic detail, while broad transcription records only the underlying phoneme.

Common examples help illustrate the concept. In English, the initial /p/ is often aspirated as [pʰ] in word-initial positions (as in "pin") but is typically unaspirated [p] after s-clusters (as in "spin"). These are allophones of the same phoneme /p/ in complementary distribution. In American English, the intervocalic /t/ is frequently realized as a tap [ɾ] between vowels when the second is unstressed, an allophone that can vary with [t] in some contexts. The English /l/ also exhibits allophony: a light [l] at onset positions and a dark [ɫ] in syllable codas.

Allophony reflects articulatory constraints and phonotactics within a language and helps linguists describe how phonemic inventories are realized in speech. See also phoneme, allophony, phonology.