Commencement of words with the same letter

One word substitute is Alliteration.

Rhyme: correspondence of sound between words or the endings of words, especially when these are used at the ends of lines of poetry.
Alliteration: the occurrence of the same letter or sound at the beginning of adjacent or closely connected words.
Pun: a joke exploiting the different possible meanings of a word or the fact that there are words which sound alike but have different meanings.
Oxymoron: a figure of speech in which apparently contradictory terms appear in conjunction.