voicer vs utterer

voicer and utterer both are nouns.

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

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

voicer: a speaker who voices an opinion
utterer: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

Other hypernyms of voicer include speaker, talker, verbaliser, verbalizer.

voicer (noun)	utterer (noun)
a speaker who voices an opinion	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)
someone who regulates the tone of organ pipes	someone who circulates forged banknotes or counterfeit coins
	an organism that can utter vocal sounds