Communication Boards

I'm conducting some research and wanting your opinions. I have an idea for a communication device for individuals who are unable to speak. I saw a family member struggle to communicate after suffering a stroke several years ago. I really found nothing in searching that really resembles my idea. I've begun building a prototype but I have no formal medical education and was wondering if someone could give me their input. I realize that computers could probably do something similar but these can be quite expensive; and many elderly may not be as familiar with a Mac or PC as the younger generations. Please tell me, is there a need for such a device? I would want to keep this low in cost and price and lightweight. It would be a way of communicating for those permanently or temporarily disabled and unable to speak and without knowledge of signing. I thought it would even be physically and mentally therapudic. Please let me know what you think. Ask questions. Thanks so much. Garrick