stutter vs stammer

stutter and stammer both are nouns.

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

As nouns, stutter and stammer are synonyms defined as:

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

As verbs, stutter and stammer are synonyms defined as:

Other synonyms of stutter include bumble, falter.

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

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