First off, any medium to large company should already have policies and procedures on record that strictly prohibits this kind of unnacceptable workplace behaviour.
It's harassment period. Regardless of whether you're black or not. It's offensive and is not condusive to a pleasant workplace enviroment.
Now if you're working in a small company and the owner is one of the people acting the fool, then I'm not too sure what the rules are regarding that. Still, it's unacceptable and quite unprofessional. I'd start looking for other means of employment myself if the behaviour persists.
Where may I ask are you living at? I find that kind of behavior baffling seeing as how if anybody was so overtly racist like that in L.A. (or any other large Metropolis) you'd be pretty unpopular and probably would rightly get your ass handed to you by someone in less than a day.
As far as 'english only'. Now in my workplace we have fun with language. We speak in our native tounges among ourselves and even try to teach and learn new stuff from others. This one Egyptian guy has pretty much taught us all the Egyptian swear words and I've taught him all the spanish ones.
I'll just say that i don't beleive in the 'melting pot' approach to America. You don't obliterate your very identity to please the mainstream.
