I have a pal in Budapest, Hungary, and he sent me this screen shot from his iPhone 5.
Maybe the N word doesn't mean very much in Hungary? Maybe Siri is just a tad less PC than we'd expected. Either way it's funny to see the mobile personality show it's racist colours!
Edit: umataro42 says: "even if it's not faked, he also could have made "My Nigga" what his phone calls him instead of his actual name, or "sir", or "your awesomeness" or whatever."
So that explains it!