The Voder, developed by Bell Telephone Laboratory for the 1939-40 World’s Fair, was a pioneering attempt at speech synthesis. It required manual control and complex button sequences to form each syllable, making fluid speech a skill that took about a year of practice to master. Helen Harper was one of the first to effectively operate the Voder and she became the live demonstrator at the fair. She later taught a year-long course to instruct women in using the Voder, with only 20 out of 100 students graduating and matching Harper’s skills. This application allows users to experience operating the Voder and create vowel sounds using specific button combinations.
https://griffin.moe/voder/