If your child is not learning something, we need to look at how, why, and when we are teaching it. There is no age limit to learning. It doesn't matter if a person is 2 or 20 or 40. Everyone can learn a new skill at any time. As adults, we continually learn new behaviors to adapt to our environment.
Every child is an individual.
No two children are alike no matter what diagnosis they have. Although there may be similarities between your child and someone else's child, what works for that child may not work for yours. There must be flexibility in the program to allow for every child's strengths and needs. Things that are relevant to the child should be taught. I took five years of French but can't speak more than two sentences because I haven't used it.