Wolfgang Von Kempelen's Speaking Machine - Second Design

Second Design

The second design involved a console, similar to that of a musical organ of the period, in which the operator manned a set of keys, one for each letter. The sounds were produced by a common bellows that fed air through various pipes with the appropriate shapes and obstructions needed to produce that letter. Through experimentation, he came to find that the reed’s resonant length was not crucial to the creation of the high-frequency components of certain vowels and fricatives, so he tuned them all to be the same pitch for the sake of consistency between letters. While not all letters were represented at this point, Kempelen had developed the technology required to produce most vowels and several consonants, including the plosive “p”, and the nasal “m”, and thus was in a position to begin forming syllables and short words. However, this immediately led to the primary flaw of his second design: the parallel nature of the multiple reeds allowed for more than one letter to be sounded at a time. And in the process of building syllables and words, the sonic “overlap” (now referred to as co-articulation) rendered sounds very uncharacteristic of human speech, undermining the intention of the design altogether. Kempelen comments:
“In order to continue my experiments it was necessary, above all, that I should have a perfect knowledge of what I wanted to imitate. I had to make a formal study of speech and continually consult nature as I conducted my experiments. In this way my talking machine and my theory concerning speech made equal progress, the one serving as guide to the other.”
“It was possible, following the methods I’d been using, to invent separate letters, but never to combine them to form syllables, and that it was absolutely necessary to follow nature which has only one glottis and one mouth, through which every sound emerges and which gives a unity to them.”
Thus, Kempelen began work on his third, and ultimately final design, which itself was in many ways a “close-as-possible” representation of the physiology of the vocal tract.