When did kids in America start using profanity?

This black girl or rather few in my cl calls other boys the "N" word or her best friends "bitc*es" they call each other that for fun and also talks about how big some boys or his and how y he is,they write to boys saying F me.I am mixed and my grandma who is black doesn't act nothing like that nor does she talk like that.Rap music is just music and doesn't influence people unless the person listening CHOOSES to act on the negative instead of positive but I dout rap makes kids use THAT kind of language.When my grandma was growing up in the 1940's they never used that kind of language otherwise I would be hearing people my grandmas age using that on a daily basis but depending on race when did kids start using this kind of language and saying such vulgar words.Does music make kids do this?television cause theinternet is new and I dout that has any influence.