inarticulate
unarticulate
anaudic
aphasic
aphonic
breathless
brief
brusque
close
close-tongued
closemouthed
concise
curt
dazed
dumb
dumbfounded
dumbstricken
dumbstruck
economical of words
indisposed to talk
laconic
mum
mute
nonplussed
quiet
reserved
shocked
short
silent
snug
sparing of words
stricken dumb
taciturn
terse
thunderstruck
tight-lipped
tongue-tied
tongueless
uncommunicative
unloquacious
untalkative
voiceless
word-bound
wordless
aghast
daze
deaf
frantic
helpless
impotent
incredulous
livid
motionless
open-mouthed
petrify
rapt
unable
uncomprehending
unutterable
wide-eyed