Not really; Some people maybe always speak English when working, then they will speak some English words in a not English conversation even they don't know. Based on my own personal experience, the same to a native English speaker who is always speaking Chinese: one of my friend is in China, and he is a Canadians; He will speak some words even a sentence in Chinese for his friends who are only can speak English in a conversation since he is always speaking Chinese, he can't help.