Both my wife and I came to this English-speaking country 16 years ago. Our kids, Mary and Jason, are sort of teenagers now. We have been trying everything to persuade them to speaking Chinese as much as possible. Unfortunately, our Kids seldom communicate in Chinese. The only exception is that they have to speak Chinese in Chinese Language School.
Our teacher, a senior professor in Department of Foreign Language in a prestigious university in China, came to our city a week ago. We invited professor to live with us.
A couple of days later, we found that professor and our kids were talking in Chinese!!! I checked with kids and attempted to find out professor's trick. "Does professor speak English?” asked Mary. I answered "Of course". "Yes, you are right!" Jason took the conversation over "Professor’s English is so stimulating, I'd better speak Chinese now".