I've never worked that kind of job, so I don't know much. I don't understand all the other commentators suggesting going directly to your manager or even HR wi

I've never worked that kind of job, so I don't know much. I don't understand all the other commentators suggesting going directly to your manager or even HR without first talking to them, though. I think it'd be a bad idea to let this fester to that point without giving them the courtesy of a simple conversation. I wouldn't make it a big deal. One specific time you think they're probably talking about the project come over and say hi in English. If they don't switch language, ask them if they mind switching to English. Keep doing that and maybe eventually they'll realize the problem. If that fails, directly ask them to speak English when talking about work as a group because you need to be able to participate. If that fails only then do you escalate to your manager.