Autistic teen non speaker demonstrates non speaking does not mean non thinking

This non speaking teen was asked the question "what type of cloud forms in thunderstorms?" he answered on his spelling board "cumulonimbus" -- an example of a prior knowledge question in Spelling to Communicate demonstrating that non speaking or hesitant speaking in autism does not mean non thinking. Often schools and even family do not realize a non speaker can be listening the processing everything they hear. Here the method used is Spelling to Communicate.