I was doing some work in a client's house today. Both clients were from abroad but they could both speak good English. When I was doing the work, I could hear them speaking in their native language.
I asked later if they wanted more work doing at another time. They then spoke in their language for a bit (not the first time they'd done that when I was there and with them) before answering me in English.
I do feel a bit strange when such things happen. It's happened at some other places I have worked at where conversations have happened around me in a native language.
AIBU to expect people who can speak English to speak English when I was with them?