And of course if you haven't read Dave Hingsburger's booklet,
The Are Word, it is certainly worth your time. It is about empowering people with intellectual disabilities to understand bullying and teasing and how to deal with it.
Another interesting site on this topic are the various videos of a speech made by a high school student on this topic. He relates its use to racist language and as he is the brother of a girl with intellectual disabilities, it is very moving.
As always, if you would like to borrow either of these items or anything else, please email the library.