It is very likely that being cussed at is a violation of your rights. Cursing can obviously create a hostile work environment and may be part of a larger harassment claim. You should document anytime you are cursed at or have other inappropriate language spoken to you at the workplace. Additionally you shoud document any witnesses that are aware of the language. Some people curse inappropriately out of habit with no intent to be offensive. Tell your boss that you feel uncomfortable with it and ask him to speak to you with respect for your discomfort. If that doesnt work take your evidence to HR and to an attorney.