Well... In the United States, only a slim number of people know a second language, so it hasn't happened to me personally, but it sounds pretty rude. Especially if they changed the language exclusively when you're around, but I honestly have no idea.

I noticed that most people with a immigration background here do that as soon as germans come into hearing range.*sighs*

*Hugs you tightly* I'm sorry to hear...

*snuggles up on you* Meh, it´s nothing to be sorry about. It´s more a nuisance than anything else and I am propably the only person around to give it that much attention.

*Snuggles back and pulls you close* Yeah, I bet. It sounds pretty rude anyway.

That happens fairly often here in the UK. More often than not in the gym changing room it's mostly just shouting in Polish. I just get used to it. Quite often it's Polish or European in some way. The main annoyance for me is that it makes me very conscious of my failure to fully learn a second language. Other than that I get fairly used to it.

Maybe an old topic, but one that comes up more often where I live, Arizona, a Southwestern border state in the United States. Where I work there are several that are fluent in Spanish often choosing to speak it over English when talking to each other. It maybe that they prefer to speak Spanish, and I'll admit maybe I would too, but I often feel the odd man out not being very fluent.

Irony of it is took two courses of Spanish in High School and a my dad's former last name (changed due to adoption) being Spanish in origin! And still only can read and write better than I can speak the language.