I teach in Mexico and in my classes I don't hesitate to explain things in Spanish. At the university where I work we regularly debate on whether or not and how much Spanish we should use in the classroom. The general consensus is that a little is OK.

I am heading to Korea next month, and I won't have the option of speaking Korean (at the moment I can't speak any Korean) in English classes. I was wondering how many teachers in Asia CAN speak their students' language and if those that can use it much in class.