mind/watch your language

mind (one's) language

To speak in a calm and polite manner; to not speak in a rude, hostile, or inflammatory manner. 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!
See also: language, mind

mind/watch your ˈlanguage

be careful about what you say in order not to upset or offend somebody: Watch your language, young man!
See also: language, mind, watch