Why is the ninth month called September?
late 14c., "expression of discontent by grumbling," from Old French murmure "murmur, sound of human voices; trouble, argument" (12c.), noun of action from murmurer "to murmur," from Latin murmurare "to murmur, mutter," from murmur (n.) "a hum, muttering, rushing," probably from a PIE reduplicative base *mor-mor, of imitative origin (cf. Sanskrit murmurah "crackling fire," Greek mormyrein "to roar, boil," Lithuanian murmlenti "to murmur"). Meaning "softly spoken words" is from 1670s.
murmur mur·mur (mûr'mər)
An abnormal sound heard on auscultation of the heart, lungs, or blood vessels.
in phonetics, a speech sound or quality used in some languages, produced by vibrating vocal cords that are less tense than in normal speech, which produces local turbulence in the airstream resulting in a compromise between full voice and whisper. English speakers produce a vocal fry when suggesting ghost wails with an oo-sound. See also voice; whisper.