Sometimes common sense just comes into play. My workplace is a multicultural experience, which is cool. A few staff members are from Latin American countries, and they often speak to me in Spanish. I have no shame about being a Spanish speaker, and I certainly have shame about my ethnicity, but I was raised with the concept that it's rude to speak Spanish (or any language) if there are people in the room who don't know the language. The only language *everyone* in my workplace speaks is English. I always answer in English. Based on how I was raised, and what I believe, it's the polite, common sense thing to do. My co-workers view this as an indication that I am "not PC", that I'm down on the Spanish speaking population - which couldn't be further from the truth.
I've actually had a very green, idealistic co-worker ask "If you're not willing to be PC, why did you get a job in this field?" My answer is pretty much that I don't believe the efforts to move towards equity should have ever been so confused with pandering to the unreasonable demands of a select few in the name of political correctness...or with the inability to exhibit a sense of humor.