It is sometimes difficult to know how to commmunicate with people with disabilities without feeling awkward. For a period of time I drove a blind social worker around to her appointments and I learned a lot from that experience. People would sometimes try to address me instead of her, like if we were ordering at a fast food restaurant. She said, "I'm blind, not deaf!" She helped me understand that it was ok if I sometimes did not use the politically correct terminology (like saying "visually impaired" instead of "blind") She was not sensitive because she knew I was being respectful. I think that is the key--just acting natural and treating a disabled person like they were anyone else, and through your interactions you will gradually learn how to communicate better.
I think another key reaction mentioned in the module is to always ask them if they need help instead of assuming it. One of my coworkers with a walking impairment fell one day and another coworker tried to assist him. He protested against any kind of help very vehemently. It is a natural reaction for most of us to want to help, but many disabled people have worked hard to reach their level of independence and don't want to "regress".