aspiration
bated breath
breath
breathy voice
drone
droning
exhalation
gabble
gibber
gibbering
inarticulate
indistinct
jabber
jibber
little voice
low
low voice
maundering
mouthing
mumble
murmur
murmuration
murmuring
murmurish
murmurous
mutter
muttering
rustling
sigh
soft voice
stage whisper
still small voice
susurrant
susurration
susurrous
susurrus
underbreath
undertone
whisper
whispering
whispery
chew
chewing
diction
enunciation
manduction
mastication
bumbling
crumbling
fumbling
grumbling
humbling
rumbling
stumbling
tumbling