I thought she was acting foolishly, but I 'bit my tongue' [='held my tongue'] and didn't say anything.
The news of their engagement 'set tongues wagging'. = 'Tongues were wagging' over their engagement.
He speaks English fluently but his 'mother tongue' [='native language, first language'] is Chinese.
(..) and stay true in the face of danger and death? Mr.Cotton! Answer, man! He's a mute. Poor devil had his tongue cut out. He trained the parrot to talk for him. No one's yet figured how. Mr.Cotton's parrot. Same question. (..)2003 Pirates of the Caribbean: The Curse of the Black Pearl