Allofonia

Allophony, or allofonia in some languages, is a linguistic phenomenon in which a single phoneme has two or more distinct phonetic realizations called allophones. These allophones are non-contrastive, meaning that substituting one for another generally does not change the meaning of a word.

Allophony arises from phonological rules or articulatory processes that govern how sounds are produced in specific environments. Allophones typically occur in complementary distribution, where different realizations never appear in the same phonetic context, or in free variation, where speakers may use either realization without changing meaning.

A classic example from English is the aspiration of voiceless stops. The phoneme /p/ is realized as [pʰ] in most syllable-initial positions (as in “pot”) but as [p] after an initial /s/ cluster (as in “spot”). Another well-known case is the intervocalic t/d alternation in American English, where /t/ or /d/ becomes a voiced alveolar tap [ɾ] between vowels when the second vowel is unstressed (as in “water” pronounced with a quick, soft pronunciation).

Allophony helps explain how languages can use a limited set of phonemes to produce a wide variety of sounds while maintaining perceptual distinction and phonological structure. The concept is foundational in phonology and supports the analysis of pronunciation, orthography, and dialect variation. The term derives from Greek allos meaning “other” and phone meaning “sound.”