murmuring
Tom no está murmurando.
Tom isn’t mumbling.
Tom está murmurando, ¿no lo está?
Tom is mumbling, isn't he?
Tom parece estar murmurando.
Tom seems to be muttering.
You are mumbling.
He's muttering something.
Ella está murmurando consigo misma.
She is muttering to herself.
Tom está murmurando.
Tom is muttering.