The same phoneme does not always sound identical. An allophone is a context-conditioned 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. A contrast that is phonemic in one language may be allophonic in another.

Phonologists find allophones by checking complementary distribution and the absence of minimal pairs. Narrow transcription forces students to notice detail their native phonology usually filters out. Allophonic rules form a core part of any language’s sound pattern.

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