Vocoders, (voice encoder-decoder, they effectively compress voice) which were going to enable computers (the analog kind) to respond to human speech in callcent

Vocoders, (voice encoder-decoder, they effectively compress voice) which were going to enable computers (the analog kind) to respond to human speech in callcenters (because editing/generating the compressed stream is hard, but actually doable) Of course it was a joke. But ... it was used. What they were used for a little bit is voice encryption, in military communication. Vocoder -> encrypt -> transmit -> decrypt -> Vocoder and you can "talk", if you don't mind the extreme voice distortion. Oh and the talking clock on the telephone network. That, they got working.