| This dissertation examines the speech and hearing studies conducted by telephone engineers in the first half of the twentieth century and their significance to the history of information theory and cybernetics. Telephony resulted from "applied phonetics": a merger of the physics of sound, the physiology of the ear and vocal organs, and the psychology of speech perception. Human constraints became molds for the design of efficient telephone apparatus. Through research in over thirty manuscript and instrument collections, I situate deafness and deaf people at the heart of communication engineering. Deafness instructed engineers, some themselves deaf, about the ways "information" could be extracted from speech and signals economized, modulated or transmitted through different media.;Collaborations between American Telephone and Telegraph (AT&T) and the New York League for the Hard of Hearing in the 1920s yielded the electronic audiometer, a means to survey "normal" American hearing and measure the "deafening" effect of noise in communication systems. The vocoder---a technology central to early digital signal processing---relied on lip-reading and mechanical larynges as prototypes for sampling and modulating speech. During World War II, Bell Telephone Laboratories hired a deaf engineer and two experts on deaf education to help develop the sound spectrograph, a device for portraying harmonics. Spectrograms were used to identify the "information" content of speech, to provide for visual telephony, and to normalize deaf oral pronunciation through feedback. Norbert Wiener later drew on the principles of the vocoder and the spectrograph (analysis, compression, feedback) to construct a "hearing glove," which he tested on Helen Keller.;Throughout the twentieth century, various firms repurposed telephone components into hearing aids. I describe the debts electronic miniaturization and circuitry owe to these aids, with their dual demands of portability and invisibility. Lastly, I trace the history of cochlear implants---and the possibility for direct electrical communication with the brain---to the telephone theories and equipment that began to move into psychoacoustic laboratories in the 1930s. |
