How do you respond when someone tells you to watch your language?

Tell her if she has a problem then deal with it. If you want to have her telling you what to do just dont listen to what I say.

Just because cursing is acceptable by today's standards, does not mean that it is attractive, nor does it make you seem mature, intelligent, and poised. I think you should consider it a favor that your friend asked you to care about what you say and how it is spoken. Trashy is how you come off when you use swear/cuss words instead of increasing your vocabulary so that you can express yourself with words that will get your point across without offending others. It is time for all to see that it is NOT "all about you".... this attitude is the surest way to a miserable existence for all.... instead, determine that YOU will not be a part of the problem but will become a piece of the solution... and that means to care more for others than for yourself. And, start with accepting your friend's request.