There are two key factors to communication, understanding the thoughts expressed by others and expressing ones own thoughts. "Voice is a preferred means for person-to-person communication. The acoustic signal conveys a sequence of audible sounds- speech- whose meanings (within cultural groups) have been agreed upon a priori. This acoustic code constitutes language"[JF90]. Therefore, communication in a preferred way occurs within the realms of speech and hearing (speech recognition). The concept of real-time is a key issue when we consider interaction with the general population. The American population tends to lack the patience required to interact with disabled persons for extended periods of time if it is not on a real-time or near real-time basis[KB93] (near real time refers to conversation held between the 20-120 words per minute[IF87]). For completeness a possible augmentative "hearing" system will be looked at first, followed by augmentative communication systems (where this project makes its contribution).
One method of regaining "hearing" for a disabled person is through a speech recognition system. The applications for speech recognition extend beyond just hearing and have great potential in other main stream and augmentative areas, " . . . The scope of which covers information distribution, entertainment, voice messaging, transactions, and education"[DF90]. There is a great deal of research that has gone into this area, and some conclusions have been reached. It is import that there be a large vocabulary (1000+ range), speaker independence (ability to recognize multiple accents), continuous speech recognition (recognizing speech taken from fluent sentences), and word spotting (focusing on the key words in casual speech)[AS91][CV89][JW90]. Once we have conquered voice we are more than half finished. All that remains is "displaying" the information in a form that the disabled person can understand. This part needs to be customized for the individual; some examples of "displays" include:
The other aspect of communication aides is regaining the ability to "speak", the area in which this project makes its contributions. This "speech" is regained by means of an aide whereby disabled persons can communicate their thoughts to the public at large. This aide can be broken down into three subparts: interface, feedback, and output. The interface provides a method for clients needing the aide to select words or phrases to express their thoughts. This must be customized to the client needing the device and their individual abilities. Some selection interfaces include:
Feedback to the client is often done by pictures on the selection items called icons (see Communication Device Basics), text displays, or on the output of the device itself. Hopefully, speech is the output of the device or aide (see Basic Communications above). It usually takes the form of a synthesized (computer generated) or a digitized (recorded from human speech) voice. These three parts-the interface, feedback method, and output, are put together in a communication device/aide that will help enable clients to communicate their thoughts and needs.
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