Here in Israel, most people don't realize that what they are saying is offensive to English speakers. People will regularly drop F-bombs and other such words. It's in music played publicly. (The twelve-year-old girls were dancing to music with a lot of foul language for a while.)
I'm a native English speaker. (Brits may disagree with that though :D) I've tried to get the point across to some people - I've said that word is about the worst word you can say in English. Please don't use it. but it doesn't seem to have gotten the point across because they're still using them around me. This is not specific to my age group - I know that teenagers will swear - but even some adults. They don't seem to understand.
How can I get the point across and ask them to not be so foul mouthed?