I have been an ESL teacher fro about 3 years now. I have had a class where all the students shared the same native language. Also, I have had classes where only a few of my students shared a native language with one or two others in the room.
What I have learned is that differentiation is a non-negotiable when teaching a group with various native languages. The Arabic speakers will grasp concepts differently than the Spanish speakers and the Spanish speakers will grasp concepts differently than the Chinese speakers.
The best way I have learned to instruct a group such as this is using centers. Has anyone tried something anything else to best instruct a group of students who have so may different language backgrounds?