Anne is correct that differentiation is not just adout thick/clever. I am a Teacher of the Deaf. I want staff with Deaf students in their class to speak clearly to them, giving them a good view of the mouth and using their amplification equipment, rather than talking whilst facing the board. I want them to stop using pop music as their example for everything. I want them to show videos with the subtitles switched on. I want them to ... well, differentiate, really.