murmur

mummel, mumla

1. (countable, uncountable) Any low, indistinct sound, like that of running water.

2. (cardiology, medicine) The sound made by any condition which produces a noisy, or turbulent, flow of blood through the heart.

3. A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; any expression of complaint or discontent.

4. (intransitive) To speak or make low, indistinguishable noise; to mumble, mutter. [from 14th c.]