A speech synthesizer invented at Bell Labs in 1938. The Voder was basically the back half of a vocoder -- the resynthesis half -- mated to an oscillator for producing vowel sounds, and several types of noise generation for producing consonant sounds. Rather than encoding a human voice input, the Voder was instructed what sounds to produce by an operator pressing keys at a console. The keys and other operator controls allowed the operator to produce vowel and consonant phonemes, control the pitch of the vowel sounds, and slur and accent phonemes in order to produce somewhat natural-sounding speech rhythms.
The Voder was built as a basic-research project into the nature of speech, as part of the Labs' ongoing effort to find more bandwidth-efficient ways to transmit the human voice (something that would benefit AT&T, the Labs' parent company, in terms of being able to carry more telephone conversations on a given cable). The Voder was demonstrated, and caused a sensation at, the New York World's Fair in 1939. Twelve operators were trained to perform demonstrations with it; reportedly it required a quite skilled operator to produce understandable speech.
The Voder saw little use after the Fair, and was eventually put into storage. For many years afterwards, it was unaccounted for. SSL proprietor Doug Slocum found and photographed parts of it in a New Jersey warehouse in 2015; see here.