Lot's of rudeness going around these days I guess.
I'll usually turn to whomever I'm walking with, slightly nod toward the Spanish-(or any other language, for that matter)-speakers, rattle off a little bit of Anglo-Saxon or Old Icelandic, and then grin knowingly. It's soooo funny to watch them get furious over what they themselves were just doing.
We have a firm rule at work where I work with a lot of people of Fillipino descent and some of hispanic origin.
English only while working. Any language you want talking in the breakroom but not while working.
One complained “We weren’t talking about work” and the manager said “Wel; then you shouldn’t be TALKING!”
And by the way speaking with these legal immigrants I work with they are angrier than any usual American I know on the issue. They are fed up that after all they went through to get here these illegals cheat the system.
Garden variety rudeness is not what I’m concerned about. Loss of basic civility is.
Your co-workers behavior may be rudeness or it may not. Have you ever lived outside your country for an extended period. What language do you guess you’d be talking to your fellow Americans in under those circumstances? I’ve found myself in this situation many times, among English Speakers and among French speakers. I can tell you that you will (despite your best efforts) tend to switch to your native tongue again and again. It is just hard-wired in your brain.