The same phoneme does not always sound identical. An allophone is a context-dependent phonetic variant of a phoneme that does not change word meaning in that language.

English aspirated [pʰ] in pin and unaspirated [p] in spin are allophones of /p/. Speakers treat them as “the same sound” even though instruments show clear differences. Which variants count as allophones is language-specific; a contrast in one language may be automatic variation in another.

Phonologists discover allophones by checking for complementary distribution and lack of minimal pairs. Transcription practice forces students to notice details their native phonology usually filters out. Allophonic rules are a core part of a language’s sound pattern.

• Predictable phonetic variant of a phoneme
• Does not create meaning differences in the language
• Often in complementary distribution
• Language-specific rather than universal