In America, you can say n*gger all you want, and it’s considered protected speech under the Constitution. Even though free speech is not absolute, it does still protect people from being prosecuted over insults, even if those insults are racially motivated.
In the United Kingdom, however, you can be prosecuted for hate speech. One man who used the N-word to address a black man found this out the hard way. Christopher Jones was initially charged by local authorities and courts with racial abuse for using the word.