find (one's) tongue
To regain the ability to speak, especially after feeling frightened, nervous, or at a loss for words. It took him a minute, but Pete found his tongue again after we startled him at his surprise party. The little boy, who had been huddled nervously at the back, found his tongue and told the detectives what happened.
find one's tongue
Fig. to be able to talk; to figure out what to say. Tom was speechless for a moment. Then he found his tongue. Ann was unable to find her tongue. She sat there in silence.