Imagine you have a friend who often uses vulgarities and like they say has a bad mouth. You want to give them advice and ask them not to use vulgar language as a friend who wants the best for him/her. Also you dislike his/her mannerism, but for some reasons you can not put an end to this friendship (you want to maintain that relationship.) Once, when he/she is talking to you about a serious matter, he/she starts cussing and mixing their words with some of his personal catchwords which everyone would consider them indecent.

I need to know whether the sentence bellow sounds natural to you and if not, what is the natural way to say:

  • Don’t be a foul-mouthed person.
  • 2
    Downvote removed. You should try not to cuss so much.
    – TimR
    Mar 25, 2017 at 15:22
  • 2
    An actual friend could speak honestly. I'd say, "When you use the 'f' word/swear words as your main adjective(s), it makes others assume that you are not as educated/well-spoken/smart/interesting as I know you are." Other phrases might include, not family-friendly; impolitic; potty-mouthed; low-brow, dirty-mouthed... or simply: "Please do not swear."
    – WRX
    Mar 25, 2017 at 17:22
  • There is a somewhat old-fashioned expression: "You kiss your mother with that mouth?" That would probably only be appropriate with a friend or close co-worker, but in that situation it might come across as a little more light-hearted.
    – Mark Meuer
    Nov 6, 2017 at 21:44

4 Answers 4


The expression thatt you suggested does not sound natural. It would be slightly better as

Don't be foul-mouthed.

The following expressions are widely used: the appropriate expression would depend on how well you know the person.

watch your mouth - this quite aggressive, and would be used with somebody that you don't know... this could get you into trouble if you said it to somebody that is bigger than you.

don't be vulgar - this is firm but not aggressive. You could say it to somebody whether or not you know them.

mind your language - this expresses mild disapproval: you might use this to somebody that you do know

not in front of the children- if a friend lets slip an inappropriate word: this can be used even if no children are present.

wash your mouth out with soap - a parent could say this to a child, or you could say it to a friend to make a good-humoured criticism.

  • 4
    Do you talk to your mother with that mouth?
    – TimR
    Mar 25, 2017 at 15:08
  • "Not in front of the children" might imply that you consider some nearby third parties to be "children," so use with care.
    – Kevin
    Mar 25, 2017 at 22:35
  • @TRomano I didn't follow you when you mentioned "Do you talk to your mother with that mouth?" to JL! Did you mean that it sounds too childish to be said to an adult?
    – A-friend
    Mar 28, 2017 at 8:14
  • 1
    It is a common saying that means "Would you use that sort of foul language in the presence of your mother?" I believe the underlying appeal is to reverence and respect, but in a semi-jocular, semi-reprimanding manner.
    – TimR
    Mar 28, 2017 at 10:54

I think polite company is a useful phrase to suggest that someone might moderate their behaviour when around certain people. Such as:

We are going to be in polite company - to remind someone should refrain from being vulgar, swearing or telling off colour jokes, etc.

To admonish someone for use of a specific word/topic - That's not a word/topic for polite company.


I wish you wouldn't swear like that all the time.

You should only have to say this once. Your friend might be surprised, but they will remember it.

  • Thank you very much @TonyK, but I doubt weather the word "swear" encompas the f words or not!
    – A-friend
    Mar 28, 2017 at 8:03
  • It certainly does, in British English at least.
    – TonyK
    Mar 28, 2017 at 10:52

There are two separate issues here:

  1. The interpersonal issue of asking your friend to swear less (for which you may get better advice in the Interpersonal Stack Exchange site)
  2. How to word the request in a clear manner.

The phrase that I would use for the latter is

watch your language

See for example Watch Your Language: Swearing in News Stories, an article about swear words in news stories, and this classroom poster:

classroom poster with admonishment "watch your language"

You might also point out to your friend that the less you swear, the more effective it is.

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