Murmur, mumble, mutter mean to make sounds that are not fully intelligible. To murmur is to utter sounds or words in a low, almost inaudible tone, as in expressing affection or dissatisfaction: to murmur disagreement. To mumble is to utter imperfect or inarticulate sounds with the mouth partly closed, so that the words can be distinguished only with difficulty: to mumble the answer to a question. To mutter is to utter words in a low, grumbling way, often voicing complaint or discontent, not meant to be fully audible: to mutter complaints.

Did you mean unmurmuring?