Unfortunately language has become a stand-in for race and culture, and it has somehow become an icky topic because, as you exemplify, some people are downright

Unfortunately language has become a stand-in for race and culture, and it has somehow become an icky topic because, as you exemplify, some people are downright scared to even approach that subject for fear of being labeled a racist or an “asshole”. Let’s just completely separate the two and focus on the facts: your teammates are speaking in a language you don’t understand, in a more or less official capacity; it doesn’t matter what language it is, but what does matter is that it’s a problem and it leaves you and possibly other team members feeling uncomfortable. And believe it or not it’s ok to feel uncomfortable. I speak another language as well, and I would be ashamed to speak it with ANYONE in front of mixed company because it’s just rude. So your colleagues are being rude whether they realize or not. If I were the TL or PM I would politely mention in a team meeting that some people feel uncomfortable when others speak a language we don’t all understand and to please be considerate of others in those situations. No need for a reprimand or direct confrontation.