silent movement of the lips in simulation of the movements made in audible speech.
muttering; mumbling; murmuring.
Origin of mussitation
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Movement of the lips as if speaking but without sound.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.