mind/watch your language
mind (one's) language
To speak politely, without using profane, obscene, or rude language. Often used as an imperative. You mind your language, young lady, or you'll be grounded for the weekend! We've been trying to mind our language around the kids. They're at the age now where they'll start repeating everything we say!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
mind/watch your ˈlanguagebe careful about what you say in order not to upset or offend somebody: Watch your language, young man!
Farlex Partner Idioms Dictionary © Farlex 2017