physical working model of the human vocal tract (late 1800s).
"Von Kempelen's efforts" [to build a model of the human vocal tract] "probably had a more far-reaching influence than is generally appreciated. During Alexander Graham Bell's boyhood in Edinburgh, Scotland (late 1800s), Bell had an opportunity to see the reproduction of von Kempelen's machine, which had been constructed by Wheatstone. He was greatly impressed with the device. With stimulation from his father (Alexander Melville Bell, an elocutionist like his own father), and his brother Melville's assistance, Bell set out to construct a speaking automaton of his own."
"Following their father's advice, the boys attempted to copy the vocal organs by making a cast from a human skull and molding the vocal parts in guttapercha. The lips, tongue, palate, teeth, pharynx, and velum were represented. The lips were a framework of wire, covered with rubber which had been stuffed with cotton batting. Rubber cheeks enclosed the mouth cavity, and the tongue was simulated by wooden sections -- likewise covered by a rubber skin and stuffed with batting. The parts were actuated by levers controlled from a keyboard. A larynx 'box' was constructed of tin and had a flexible tube for a windpipe. A vocal-cord orifice was made by stretching a slotted rubber sheet over tin supports."
"Bell says the device could be made to say vowels and nasals and could be manipulated to produce a few simple utterances (apparently well enough to attract the neighbors). It is interesting to speculate about how this background may later have been influential in creating U. S. Patent No. 174,465, dated 14 February 1876 -- perhaps one of the most valuable in history."
J. L. Flanagan, "Voices of Men and Machines", Journal of the Acoustical Society of America, 1972, vol. 51, pp. 1375-1387.
A. G. Bell, "Prehistoric Telephone Days", National Geographic Magazine, 1922, vol. 41, pp. 223-242.