alliterator vs utterer

alliterator and utterer both are nouns.

Word	Noun	Adjective	Verb	Adverb
alliterator	Yes	No	No	No
utterer	Yes	No	No	No

As nouns, utterer is a hypernym of alliterator; that is, utterer is a word with a broader meaning than alliterator:

alliterator: a speaker or writer who makes use of alliteration
utterer: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

Other hypernyms of alliterator include speaker, talker, verbaliser, verbalizer, author, writer.

alliterator (noun)	utterer (noun)
a speaker or writer who makes use of alliteration	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)
	someone who circulates forged banknotes or counterfeit coins
	an organism that can utter vocal sounds