Long ago, Carin put up audio of a history of different speech synthesizers meant to show how the technology has evolved through the years. Included in that demonstration was the Voder, a device first shown by Bell Labs in 1939. What you heard back then was only a few seconds of it, but because the internet is an amazing place, we can now watch six minutes of that presentation.
And here’s an explanation of how it worked. TLDR: it was complicated as hell and almost no one could figure it out.
The Voder was a beast to operate. The machine could create 20 or so different electric buzzes and chirps, which the operator would manipulate using 10 keys, a wrist plate, and a pedal. The spectrum of buzzes and hisses could be orchestrated to mimic speech using the 10 keys to play a range of sounds, which could switch between voiced (anything that uses the vocal cords, like “uuuuh”) and unvoiced sounds (sounds that don’t use the vocal cords, like “sssss”) with a click of the wrist bar, while the pedal would affect the pitch of the “voice,” which could create a range of inflections.
Creating words with the Voder required thinking about the various sounds that combine to create a single word, and the subtle changes that affect its meaning. It was a difficult and unnatural process, and only between 20-30 people ever even learned how to use it.