1. Assonance: repetition of internal vowel sounds
Assonance differs from RHYME in that RHYME is a similarity of vowel and consonant.
Rhyme: Lake, Fake
Assonance: Lake, fate
Note its complex employment in the first STANZA of Thomas' "Ballad of the Long-Legged Bait":
The bows glided down, and the coast  Blackened with birds took a last look  At his thrashing hair and whale-blue eye  The trodden town rang its cobbles for luck.
Poets may employ assonance to enhance the musicality of the poem, or to create mood and tone.