keep a civil tongue

keep a civil tongue

To speak kindly and politely; to refrain from using harsh, insolent, or rude language. I don't want any outbursts between you and your sister during this dinner, so please keep a civil tongue, understood? I know that this is a heated topic, but I would ask that all participants in the debate please keep a civil tongue.
See also: civil, keep, tongue
Farlex Dictionary of Idioms.

keep a civil tongue (in one's head)

Fig. to speak decently and politely. Please, John. Don't talk like that. Keep a civil tongue in your head. John seems unable to keep a civil tongue.
See also: civil, keep, tongue
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • mind (one's) language
  • mind/watch your language
  • watch (one's) language
  • keep a civil tongue in (one's) head
  • keep a civil tongue in one's head
  • keep a civil tongue in your head
  • lip
  • if you don't mind
  • If you don't mind!
  • look at cross-eyed
References in periodicals archive
At the same time, he should have told the woman to keep a civil tongue in her head.
Just Joan : 'It was my first big Christmas dinner and she criticised everything'