I had Turkish and Greek friends who told me they did exactly this. So although you might not others most certainly would.
I have no problem with people speaking another language in my presence but chatting to each other while people are waiting to be served or being served is a no no.
I have no idea why jobs are in fact harder to get and keep due to all these assessments and training etc ( sorry not sure what they are actually called ) why service is so much worse.
its like driving tests get harder and harder but driving standards have lowered