I recently talked to a parent whose son was able to order food from a restaurant menu for the first time by himself using an iPad to communicate. Apparently, these new-fangled computer machines do all kinds of amazing things that make communicating and understanding easier for children with learning difficulties.
Through the Website Bridges4Kids, I found a list by Eric Sailer of dozens of apps for iPads, iPhones, and iPods. They teach communication skills, sign language, math and spelling, help with speech problems, provide interactive games and books, help with organization, and many other things. These are available through the iTunes store and have reviews that will help parents determine which apps will be the most suitable to their child's needs.