mumbling

(noun) indistinct enunciation.

(noun) ineffectual chewing (as if without teeth). Synonyms: gumming.

(verb) talk indistinctly; usually in a low voice. Synonyms: mumble, mutter, maunder, mussitate.

(verb) grind with the gums; chew without teeth and with great difficulty. Synonyms: mumble, gum. Example: "The old man had no teeth left and mumbled his food."