The other situation that I want to tell you about is mine. When I went to high school, I was living in Toronto and I was attending Étienne-Brûlé School, a French-language school. I had come from Quebec, and so I spoke French well. However, in the schoolyard, no one else spoke French. I would go to parties where everyone would be speaking English and I would not understand anything.
Now, we are talking about teenagers. It is a little bit more difficult to convince teenagers to continue speaking French.