This chapter lists some of the key inventions and applications in the history of computer synthesized speech (CSS). Starting with a brief look at the early synthesis machines—precursors to the computerized renditions of the 20th century—the chapter proceeds to look at the strides made by corporations, such as Bell Labs, IBM, Apple Inc., and Microsoft, in creating assistive technologies that tap into the benefits of CSS. There is also a discussion on developments in the fields of Neuroscience, Robotics, and the non-scientific fields of Composition and the Arts. Finally, the chapter explores how CSS has permeated the popular culture mediums of film and television, sometimes in parallel and sometimes as antecedents to current day inventions.
TopIndividual Innovation
As is the case with many modern technologies produced en masse today, we have the inventive spirit of individuals to thank for laying the groundwork to today’s computer synthesized speech. Researchers point to 18th century Europe as the birth place of mechanical speech synthesizers. Wolfgang Ritter von Kempelen, a Hungarian nobleman, engineer, and government official, invented one of the first synthesizer machines (Coker et al., 1963; Schroeder, 2004). According to Manfred Schroeder’s research (2004), von Kempelen began development of his earliest “speaking machine” in 1769, designing it from wood and leather to replicate the functions of human lungs, vocal cords, and vocal tracts. The mechanism was manually operated, with air blown through the various parts to produce sounds (Cater, 1983). The first rendition of the machine created vowel sounds. A later version had a “tongue” and “lips” that enabled it to produce consonants with plosive sounds, “such as the b (as in bin) and d (as in din)” (Schroeder, 2004, p.26). It is unclear why von Kempelen decided to make the device. During the period of his inventions, there was a growing interest in “spring-operated automatons” that replicated human actions (Coker et al., 1963, p. 3). This could have influenced his decision to make the speaking machine, and to subsequently publish his 1791 book documenting his work. What is noted, however, is that von Kempelen’s “early forays into synthetic speech stimulated much research into the physiology of speech production and experimental phonetics” (Schroeder, 2004, p. 26).
Paralleling von Kempelen’s work was Christian Gottlieb Kratzenstein’s 1779 entry into the Imperial Russian Academy of St. Petersburg’s annual competition. Kratzenstein, a physiologist, won the competition by providing the best explanation of the physiological differences between five vowel sounds, along with his construction of a model made of resonators that could produce those sounds (Cater, 1983; Coker et al., 1963; Schroeder, 2004). Like von Kempelen’s device, Kratzenstein’s invention was modeled after the human vocal tract, and produced sounds by manipulating airflow over vibrating structures or reeds. It too was not automated, requiring someone to operate it.
By the nineteenth century, Sir Charles Wheatstone built upon ideas from von Kempelen’s machine and the theories purported by Kratzenstein and one W. Willis of Britain. Kratzenstein and Willis independently theorized that machine-generated vowels could come from “different shapes having identical resonances” (Schroeder, 2004, p. 27). Using this knowledge in combination with his musical expertise, Wheatstone made his own speaking machine—a more sophisticated rendition of the von Kempelen device (Cater, 1983).