chew vs mumble

chew and mumble both are nouns.

Word	Noun	Adjective	Verb	Adverb
chew	Yes	No	Yes	No
mumble	Yes	No	Yes	No

As verbs, mumble is a hyponym of chew; that is, mumble is a word with a more specific, narrower meaning than chew:

Other hyponyms of chew include champ, chomp, champ, gum, chaw, crunch, munch, gnaw.

chew (noun)	mumble (noun)
biting and grinding food in your mouth so it becomes soft enough to swallow	a soft indistinct utterance
a wad of something chewable as tobacco

chew (verb)	mumble (verb)
chew (food); to bite and grind with the teeth	talk indistinctly; usually in a low voice
	grind with the gums; chew without teeth and with great difficulty