whisper, hum, groan, roar, gasps, howls, shrieks, squawk, mutter, sighs, din, thrum, shrilling, gurgle, sotto voce, hiss, squeals, whirr, wail, titter, whine, yawn, shouts, moans, hallelujahs, clatter, cries, grumbling, droning, ululation, cacophony, screams, throb, yelps, rumble, mumble, burble, growl, chirp, bleats, harrumphing, whir, hoofbeats, chattering, exclamations, chirrup, whinnies, guffaw, peals, tintinnabulation, clucking, palpitate, croaking, snickering, snuffling, mooing, sob, rustle, bellowing, hoots, commotion, braying, splutter, clop, tremble, oinks, chitter, clap, giggles, bawl, flutter, cooing, snigger, peep, clamor, cackles, hurrahs, shiver, chunter, purr, smirks, whimpers, screech, keening, puzzlement, trill, warbling, gooseflesh, bewilderment, cacophonic, sneers, laughter, chuckles, cavil, whistling, quaver, mewing, flicker, babble, hollers, astonishment, tutting, murmurs, murmuring, murmurings, rumbling, moan, buzz, tinkle, tinkling, bruit, humming, rustling, creaking, absent, amniotic, bentonite, capsule, carbonic, cartilage, diarrhea, diarrhoea, dye, feline, fibrocystic, hallux, hydroxylase, hydroxysteroid, inhibitor, methionine, mucopolysaccharide, penis, pyridoxine, reductase

coo, susurrate, systolic murmur

acquiescence, low, low-toned, systolic murmur, unmurmuring, unprotesting

complain, complaint, kick, kvetch, mouth, plain, quetch, schwa, shwa, sound, sound off, speak, symptom, talk, utter, verbalize

cardiac murmur, croak, gnarl, grumble, heart murmur, murmur vowel, murmuration, muttering