Meaning of “murmur” - Learner’s Dictionary

murmur

verb [ I, T ] uk us /ˈmɜːmər/

to speak quietly so that you can only be heard by someone near you:

"Go to sleep now," she murmured.
He murmured a few words of sympathy.

(Definition of “murmur verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)