 [2][3]

Shortly after the completion and exhibition of his Speaking Machine, in 1804, von Kempelen died, though not before publishing an extremely comprehensive journal of the past twenty years of his research in phonetics.The 456-page book, titled "Mechanismus der menschlichen Sprache nebst Beschreibung einer sprechenden Maschine" (which translates to "The Mechanism of Human Speech, with a Description of a Speaking Machine", published in 1791)[2][4], contained every technical aspect of both Kempelen's construction of the Speaking Machine (including the preliminary designs) and his studies of the human vocal tract.