mutterer

murmur, mutter, whisper

名词 mutterer:

1. a person who speaks softly and indistinctly
   同义词：mumbler, murmurer

1. She kept on muttering to herself.
   她老是一个人嘀嘀咕咕。
2. Actors often mutter to themselves when rehearsing their lines.
   演员背台词的时候经常自己嘀嘀咕咕。