To be honest, I'm scared to post this at the risk of sounding a bit racist, but I don't intend it to be taken like that at all.
I work, in London, for a company which has an incredibly diverse employee base - being British definitely makes you a minority. I'm not going to debate whether that's a good or bad thing.
Anyway, a lot of my coworkers are from mainland Europe and frequently talk amongst themselves at the desks in their native languages. I speak semi-decent French and Spanish but nowhere near good enough to understand them (I am trying to improve though!) and I find it a bit intimidating to be sat at my desk, knowing they're talking but having no idea what they're saying. I also feel like if they are talking about work, they should speak in English so that the rest of us, even if we just overhear things, can have an idea of what's going on.
Of course, if they are talking to a French speaking client on the phone, for example, then I have no issue with them speaking French. Or if they wanted to grab a coffee and chat about personal things in their own language, good for them.
AIBU to expect that in a business environment in an English speaking country, people should be speaking English?