The ultimate goal of our research program is to develop tactile aids for the deaf and deaf-blind that can serve as substitutes for hearing in speech communication. To the extent that this research is successful, it will enable people who are deaf to achieve substantially improved speech perception, speech production, and overall language competence. In addition, it will provide increased knowledge about the basic nature of speech communication, about the general capabilities of the tactile sense, about underlying principles for the design of displays, and about sensory substitution and human plasticity. The research proposed in the application is divided into four parts. The first concerns methods of tactile communication that have evolved within the deaf-blind community and includes study of the Tadoma method, in which speech is perceived by placing a hand on the face of the talker, and also Tactile Signing and Tactile Fingerspelling. The second includes study fo Augmented Tadoma, in which the remarkable performance achieved with Tadoma is improved by adding an auxiliary tactile display of information on tongue position, and Synthetic Tadoma, in which a simulation of Tadoma that uses an artificial talking face is used as a research tool to dissect Tadoma and evaluate its components. The third compares artificial speech-reception aids that present short-term spectral information by means of homogeneous arrays of tactile stimulators. A variety of such aids are evaluated using common experimental procedures and subjects, and attempts are made to interpret results in terms of speech-parameter resolution and tactile psychophysics. The fourth involve basic study of encoding and display problems and is directed towards improved information transmission through the use of more effective encoding schemes and perceptually richer display systems.