Re: Who to call "Sensei"?
Well, as Carsten said somewhere earlier in the thread, in my surroundings, we don't normally call anyone sensei. When I talk about my teachers, I call them my teachers, when I talk to them, I call them by their first name. I think they would look at me very strangely if I calles them sensei!
The only exception are japanese teachers. Them we call sensei, both when talking about and to them.