My uncle is mentally challenged and all my childhood I remember my family calling him "slow". In my young mind I thought "slow" meant "nice" because that's how I saw him!
Now he's 64 years old and still is the NICEST person I know!
My son's aunt had Down's syndrome, so between my uncle and his aunt he grew up with people with special needs. He never asked me about them, just enjoyed them.
When he was in kindergarten, he got a new school mate with Downs. 6 years later and they're STILL good friends. One of his other years long friends is a high functioning autistic. His caring attitude and the fact that he treats them as equals has always endeared people to him. I believe the way we treated them were an example of how he accepted and respected them.
Let your daughter know that they are the same as her it's just that they need a little more help with some things. Bring up shortcomings you or someone she knows has and make her realize that everyone has them. Let her know it's not good or bad, it just is and remember to always be kind and take time to understand them. That's really all they want.
