stutter vs verbalize

stutter is a noun but verbalize is not a noun.

Word	Noun	Adjective	Verb	Adverb
stutter	Yes	No	Yes	No
verbalize	No	No	Yes	No

As verbs, verbalize is a hypernym of stutter; that is, verbalize is a word with a broader meaning than stutter:

Other hypernyms of stutter include mouth, speak, talk, utter, verbalise.

stutter (noun)	verbalize (noun)
a speech disorder involving hesitations and involuntary repetitions of certain sounds

stutter (verb)	verbalize (verb)
speak haltingly	convert into a verb
	express in speech
	be verbose
	articulate; either verbally or with a cry, shout, or noise