to speak indistinctly, stammer, or speak haltingly due to hesitation, fear, or embarrassment

to speak indistinctly or mouth words with hesitation, often used as an onomatopoeia for low speech

moving with faltering steps and speaking in a mumbling or hesitant manner, often due to nervousness

to move in a faltering or cowering manner due to indecision or fear

describing a voice that is light, soft, or low in volume

to whisper