Both alliteration and assonance are literary devices that involve repeating sounds. However, they differ in the type and placement of the sounds.
Alliteration involves the repetition of consonant sounds, usually at the beginning of words, as in “the sun sank below the serene sea.”
On the other hand, assonance involves the repetition of vowel sounds in neighboring words and can occur anywhere in the word. For example, the repetition of the “e” sound in the sentence “Hear the mellow wedding bells” showcases assonance.