The VODER machine, created 100 years ago, can speak any language, even the sounds of cows and pigs, but requires the operator to have extremely good control skills.
The first device considered a true voice synthesizer was the (Voice Operating Demonstrator) developed by engineer Homer Dudley at Bell Laboratories in the 1930s. This was a fairly complex machine with 14 keys similar to piano, a wrist-controlled stick, and foot pedals that the operator can manipulate to make the machine speak. Its sound sounded very mechanical, like “alien talking underwater”, according to Amusing Planet. In fact, the “machine voice” we often hear in old science fiction movies and TV series may have originated from VODER.
To operate VODER, the operator selects one of two basic sounds using the wrist control stick: murmur and hiss. Murmur is a basic component of vowels and nasal sounds. Hissing is a basic component of the sounds associated with consonants. These sounds are then passed through a series of filters selected by the user by selecting the appropriate key on the keyboard. The sounds are mixed and transmitted through speakers.
For many sounds that cannot be simulated by a murmur or hiss, such as “p”, “d”, “j”, and “ch”, additional filters can be selected. Different words can be combined into sentences based on keyboard control and sounds. The operator can even add expressiveness and pitch (via the pedal) depending on the question type.
Helen Harper, VODER’s chief operator, during a demonstration at the 1939 New York World’s Fair how difficult it was to master the machine. “To produce the word ‘focus’ using VODER, I had to form 13 different sounds in a row and move the wrist control up and down 5 times as well as change the pedal position 3 to 5 times in degrees the expression I want VODER to emit. Of course, all the processes need to be done with precise timing,” Harper describes.
It took Harper a year of regular practice before he learned how to operate the machine correctly. About 300 girls participated in training to become operators, but fewer than 30 mastered the skills. A skilled operator like Harper can make VODER speak any language, even making cow or pig noises. She can even make the machine sing.
Before Dudley, in 1779, Russian professor Christian Kratzenstein created a device consisting of several vibrating tubes similar to the human vocal tract. His device can produce five long vowels. Next, in 1791, an inventor named Wolfgang von Kempelen developed a more detailed machine that imitated many different human organs to create speech. The machine includes a pair of bellows to simulate the lungs, a vibrating tube that acts as the vocal cords, a skin tube that represents the vocal tract, two nostrils, a skin tongue and lips.