Text to speech
Long before there was electronic signal processing, people tried to build machines that were capable of  producing human speech. Gerbert of Aurillac (the future Pope Sylvester II) is saidf to have constructed a talking head  which was able to say yes, and no, in the year 1003. Albertus Mahnus  (1198–1280) and Rogeer BVacon  (1214–1294) are also said to have constructed machines, but no records survive. Christian Gottlieb Kratzenstein (1723-1795) built a machine in 1779, that was able to produce long vocals (a,e,i,o,u). He used modified organ pipes for his machine. The machine was called speech organ. Wolfgang von Kempelen started to develop a speech machine. In 1791, he published a paper "Mechanismus der menschlichen Sprache nebst der Beschreibung seiner sprechenden Maschine" (Mechanism of human language, besides description of its speaking-machine). Like Kempele's machine it use a set of bellows to emulate the lungs. Unlike Katzensein, he only used a mechanism with a single pipe, which is more like the human vocal tract. Other than vocals, it could produce plosives, and some fricatives. Attached to theser "vocal chords" was a formable leather tube. Von Kempelen wrote: