What do we call two words that differ from each other by only one phoneme, such as met and mat?

• A. Minimal pair
• B. Allophone
• C. Phoneme
• D. Diphthong

Answer: (A)

Two words that differ by exactly one phoneme in the same position, while sharing all other sounds, form a minimal pair. met and mat differ only in the vowel sound, with all other sounds in the same places; this single contrast shows that the two vowel sounds are distinct phonemes in English, since switching them changes the word’s meaning. This is exactly what minimal pairs reveal about which sounds are contrastive in a language.

Allophones are surface variants of the same phoneme and don’t typically create different words, so they don’t form minimal pairs. A phoneme is the abstract mental sound category that distinguishes meaning, not a pair of words. A diphthong is a single vowel that slides from one quality to another within the same syllable, unrelated to the concept of a word pair differing by a single sound.