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, grumbling, heart murmur, murmur vowel, murmuration, murmuring, mutter, muttering