The repetition of similar vowel sounds in nearby words, as in “fleet feet sweep,” is called assonance.
Assonance is a sound pattern created when nearby words repeat the same or similar vowel phonemes. In “fleet feet sweep,” the long e sound links the words even though their meanings differ. Writers and poets use this internal echo to create musicality, emphasis, mood, or a sense of movement without relying on exact rhyme.
Assonance is especially common in verse, but it also appears in prose, speeches, slogans, and song lyrics. It does not require identical spelling: different letters can represent the same vowel sound, and similar sounds may be enough to create the effect.
The closest mix-up is consonance, which repeats consonant sounds rather than vowel sounds. Alliteration traditionally repeats initial consonant sounds, as in “wild winds.” Rhyme is a related but narrower pattern involving matching sounds at word endings, often including the final stressed vowel and following sounds.