I like to add some points on this issue.
At first, don't make the foreign students feel alienated in the classroom or outside the classroom. We should encourage them to mix with the all students i.e Bangladeshi students so that they can feel comfortable to discuss any topic with their friends. Students learn best from the friends. Most of them are poor in English, no doubt. But this is our challenge to develop them.
Then we should try our level best to make a easy class lecture for all. We may know a lot on a particular topic. But if a student fails to comprehend, this knowledge results nothing. So from my point of view, make them understand rather than showing off your mastery.
Next, not only Turkish but also some local students are weak in English. So please try to include them in remedial courses.