stammerer vs verbaliser

stammerer and verbaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
stammerer	Yes	No	No	No
verbaliser	Yes	No	No	No

As nouns, verbaliser is a hypernym of stammerer; that is, verbaliser is a word with a broader meaning than stammerer:

stammerer: someone who speaks with involuntary pauses and repetitions
verbaliser: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

Other hypernyms of stammerer include speaker, talker, utterer, verbalizer.

stammerer (noun)	verbaliser (noun)
someone who speaks with involuntary pauses and repetitions	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)