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.
(..) It was going fantastic for me. And then what? And then I found out my son spent the last year being the school punching bag... ...and watched my daughter get a tongue bath from a psychopathic jackass. High school's delightful, isn't it? Yeah. But I think I was wrong about my spirit path. NED: (..)2009 17 Again