You don't have to "believe" it, it's a personal anecdote, just like yours. No conclusive evidence has been entered either way. I've worked with multiple groups

You don't have to "believe" it, it's a personal anecdote, just like yours. No conclusive evidence has been entered either way. I've worked with multiple groups of foreign nationals at multiple jobs, and no discernable pattern related to ethnicity emerged. Sometimes one group would talk in their native tongue, sometimes not. It turns out that stereotype isn't a reliable metric.