The trouble with reading machines: Exploring acoustic alphabets at Haskins Laboratories post World War II

Abstract

At the end of World War II, the American Office of Scientific Research and Development turned to Franklin Cooper and Caryl Haskins, the co-founders of Haskins Laboratories, to build working reading machines that would assist blind veterans. Reading machines were devices that converted text to sound, using acoustic alphabets to assign each orthographic character its own sound. It was expected that given sufficient user training and an optimized acoustic alphabet, anyone could learn to use a reading machine. But the Haskins group quickly discovered that even the most proficient users could only “read” a few words a minute, and speeding up the device caused letters to blur as the temporal resolving limits of the ear were reached. The failure of acoustic alphabets, even employing a range of signal parameters, led the researchers to begin analyzing speech signals with the spectrograph, then a recent invention. This series of experiments demonstrated the infeasibility of rapid word recognition by acoustic alphabets, but serendipitously set the stage to reveal mechanisms by which speech is efficiently perceived.