NETtalk

In 1986 Terrence Sejnowski and his graduate student Charles Rosenberg built a small neural network and gave it a single task: learn to read English aloud. They called it NETtalk, and what it demonstrated—audibly, unforgettably—would do more to make the connectionist case vivid than any equation could. The network saw a window of seven letters at a time, the target letter in the middle flanked by its neighbors, and produced phoneme codes fed to a speech synthesizer. During training, backpropagation adjusted its connections to reduce the gap between what it produced and what was correct. No one told it that “c” before “e” sounds soft, or how to handle a silent “e.” It extracted such regularities itself, from the statistics of thousands of words. What made NETtalk legendary was that its output was audible: you could listen to it learn. In its first passes through the text it produced formless babble;