This document discusses the difference between phonemes and allophones. It notes that a phoneme is an abstract linguistic unit that represents a set of similar sounding sounds that are in complementary distribution. Allophones are concrete phonetic variants of a phoneme that occur in different phonetic contexts. As an example, it describes /p/ as a phoneme that is realized through three allophones - [ph] initially, [p-] medially, and [pv] finally. The relationship between phonemes and allophones helps explain how sounds are represented at the phonological versus phonetic levels of language.