The sentiphone: a tactual speech communication aid.

Guiding lines in development of a speechreading aid for the deaf are presented together with some experimental results obtained with it. The principal guiding lines were to present optimal complementary information to speechreading, and an optimal utilization of tactual discriminability. The visibility of features of speech is discussed and exemplified. Reasons for the choice of tactually rather than visually presented auxiliary information are given. After a short technical description of the device, its display of phonetic features in terms of vibratory frequency and intensity is described. The experimental results consist of tests of word recognition (visually alone, tactually alone, and combined) and tests of tactual phoneme recognition.