The 1939 New York World's Fair not only had the world's most famous robot of the day, they also had a machine that gave what every robot needs: a voice.
The Bell Telephone Laboratory's Voder* was the first attempt to synthesize human speech by breaking it down into its component sounds and then reproducing the sound patterns electronically to create speech.
That sounds simple in theory and, in fact it was. The Voder actually produced only two basic sounds: a tone generated by a radio valve to produce the vocal sounds and a hissing noise produced by a gas discharge tube to create the sibilants. These basic sounds were passed through a set of filters and an amplifier that mixed and modulated them until what came out of the loudspeaker.
Unfortunately, as is often the case, what was simple in theory was extremely difficult in practice. To get the machine to actually speak required an operator to manipulate a set of keys and a foot pedal to convert the hisses and tones into vowels, consonants, stops, and inflections. And the operator needed a year's practice just to master the keys. Even then, how to get a robot to do proper talking instead of recreating pre-programmed patterns or voice from text without an operator was another level of aggravation that we're still trying to sort out.
Still, the results were impressive enough to keep the boys at Bell playing around with speech synthesis until they came up with a robot voice in the 1960s that not only talked, it sang. By The 1980s we had the SID chip in the commodore-64 that had a decent voice synthesizer, and such programs on personal computers are now common.
The term voder has pretty much gone out of fashion except for Science Fiction. But the device itself has not been science fiction since the 1930s.
In the Epiphany Trek setting the Ane have a development of the voder that takes brain waves and turns them into speech directly. It is highly useful for communicating to psionically dead races, making sure your testimony is recorded by the audio only system, or ordering from replicators that do not have a telepathic interface.
The voder can be tuned to non psionic minds as well and can over come a number of psychical difficulties temporary or permanent. Medical patients that for what ever reason cannot talk, species without a voice, and so forth. The tuning process is simple and the device easy to learn to use.