An important book by Rosemary Crossley Inability to communicate is the most devastating of all disabilities. People who can't talk can be labelled mentally retarded, or disturbed, or even vegetative, and they can't answer back. Speech is comparatively fragile, and can be lost through many forms of brain dysfunction.
Language is extraordinarily robust, and is almost impossible to eradicate completely.
What is needed is a way to access it. Speaking computers can give these people a voice, but to use the voice you have to be able to access the computer. Rosemary Crossley worked on the edge of the possible, with people who hadn't previously used any communication strategy effectively. She found that by making it easier for them to make controlled movements, so they could point to pictures, words or letters to create messages, she could release their language. The techniques she used are now known as facilitated communication.