It muttered words in a falsetto, but did not identify itself.
Apparently unaware of anything about him, he muttered dark words to himself, strange things that others could not comprehend.
On top of the hill the old man and his wife were standing next to the altar they had made, muttering words into the smoke.
After that he felt better, muttered vague words of thanks.
He muttered now and then - broken words without any meaning.
Casmir muttered soft words under his breath and turned away from the window.
Someone was mumbling on the porch, muttering words he couldn't hear.
He began to mutter words that I couldn't make out.
Ben was standing by, muttering words of counsel when requested.
They muttered low words in Italian, and their conversation took on an unusual tone.