mumble
verbUK /ˈmʌm.bəl/
US /ˈmʌm.bəl/
To speak in a quiet, unclear way so people can't understand you.
He mumbled his answer so quietly that nobody could hear him.
OTHER MEANINGS
2. To say something in a low, unclear voice because you are nervous or shy.
She mumbled an apology and looked at the floor.
3. A soft, unclear sound of someone speaking quietly.
A mumble came from the back of the classroom.
4. To speak with your mouth partly closed, making words hard to hear.
Don't mumble—speak up so everyone can hear you.