MUSSITATION
mutter, muttering, murmur, murmuring, murmuration, mussitation
(noun) a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
Source: WordNet® 3.1
Etymology
Noun
mussitation (countable and uncountable, plural mussitations)
speech conducted in a hushed manner, akin to a whisper or a murmur.
(medicine) A comatose patient's action of forming words with his lips without producing sound.
Source: Wiktionary
Mus`si*ta"tion, n. Etym: [L. mussitatio suppression of the voice, fr.
mussitare to be silent, to murmur.]
Definition: A speaking in a low tone; mumbling. [Obs.]
Source: Webster’s Unabridged Dictionary 1913 Edition