As an aside, I believe the slang term "n!gg@r" is actually a bastardization of "negro," evolved over time. I don't think it was even necessarily a derogatory epthet until American blacks began to object to it, after which some people would use it spitefully, just because blacks didn't like it.
Before that, it was just a lower class southern dialectic mispronunciation of the noun "negro," which in itself carried no more hostile meaning than calling someone a "black person."
But I could be wrong.