stammer vs stutter

stammer and stutter both are nouns.

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

As nouns, stammer and stutter are synonyms defined as:

stammer and stutter: a speech disorder involving hesitations and involuntary repetitions of certain sounds

As verbs, stammer and stutter are synonyms defined as:

Other synonyms of stammer include bumble, falter.

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

stammer (verb)	stutter (verb)
speak haltingly	speak haltingly