The power of synthesized speech took big steps ahead a century ago 

The power of speech is something no one should take for granted. Yet for centuries, people with disabilities were at a great disadvantage. 

In 2022 the centennial of the first all-electrical speech synthesis device is marked. Anyone who has waited at an airport, taken a bus or train trip, or used an automated phone voice system is familiar with speech synthesis or the artificial production of human speech, using specialized computers. Many of us with disabilities use speech synthesis devices. 

Countless advances in speech assistive technology have been made over the past century. It’s also worth recalling the efforts before 1922 to develop ways to help people speak and to provide artificial voices. The applications didn’t just aid people with disabilities. 

Creating a machine that could talk is a focus in early literature. Many people tried to build machines, called “brazen heads,” to emulate human speech and even answer questions. One early legend of such a device is tied to a man who later became Pope Silvester II. 

Another innovator was Hungarian Wolfgang von Kempelen, who in the 1770s created an “acoustic-mechanical speech machine which was operated with bellows. Other “speaking machines” followed with many inventors involved. One of them was Alexander Graham Bell, who at the same time was developing technology that led to the development of the electronic hearing aid. 

One history states, “The first full electrical synthesis device was introduced by Stewart in 1922. The synthesizer had a buzzer as excitation and two resonant circuits to model the acoustic resonances of the vocal tract. The machine was able to generate single static vowel sounds with two lowest formants, but not any consonants or connected utterances.” 

Interestingly, Stewart did little with speech synthesis after that and had a long career as an astrophysicist at Princeton. 

Others developed similar speech devices, including Harvey Fletcher of Bell Telephone Laboratory. In 1924 his device managed to produce a limited vocabulary of sounds, including vowels and words such as “mama” and “papa.” 

A big breakthrough was patented in 1937, with the VODER or Voice Operation DEmonstratoR. The VODER was a manually operated speech synthesizer invented by Homer Dudley in 1937. The VODER also came out of the Bell Labs. 

A history of the VODER states its use marked the first time that electronic speech synthesis was attempted by breaking up human speech into its acoustic components and then reproducing the sound patterns electronically. The Voder was first demonstrated at the 1939 New York World Fair. A history states: 

“The World Fair of 1939 had the most famous robot of the day, and the Voder, which could give every robot a voice! There were 20 trained operators known as the ‘girls.’ Mrs. Helen Harper was particularly skilled with the machine and her performance was applauded. The’ trained operators handled the machine much like a musical instrument such as a piano or an organ, and they managed to successfully produce human speech during the demos. In the New York Fair demonstration, which was repeated frequently, the announcer gave a simple running discussion of the circuit to which the operator replied through the Voder. This was done by manipulating 14 keys with the fingers, a bar with the left wrist and a foot pedal with the right foot.” 

Other innovations followed, with many devices available today to help with speaking.  

Want to know more about speech synthesis and other assistive technology milestones? One interesting timeline is at–pngkrT3q4uNp6oU2CE7Bfmoj 

See a picture of the VODER and read about it at  

Or learn more about the VODER at 

The History Note is a monthly column produced in cooperation with the Minnesota Governor’s Council on Developmental Disabilities. Past History Notes and other disability history may be found at