History of Professor Hawking's voice synthesizer

This content was provided by Jonathan Wood, Professor Hawking's Graduate Assistant.

In 1962 a device called The Optacon was conceived by Professor John Linvill ass a way for his blind daughter, Candy, to read ordinary print. The development was led by James Bliss and teams at Stanford University and Stanford Research Institute. Following successful demonstration of the Optacon prototype in 1969, Telesensory Systems Ince (TSI) was founded in 1970. TSI developed a line of products for the visually impaired. In 1975, James Bliss spoke with Professor Jonathan Allen and Professor Denis Klatt at MIT about TSI's interest in reading machines for the blind. This resulted in 1976 with the text-to-phoneme algorithms from the Natural Language Programming Group headed by Jonathan Allen and the phoneme-to-speech algorithms from the Speech Communications Group headed by Dennis Klatt being licensed to TSI from MIT.

Dennis Klatt based the voices on his own family, with the 'Perfect Paul' voice in DECtalk being his own (younger) voice. Professor Hawking's voice is therefore based on Dennis Klatt's own voice. Klatt was responsible for the phoneme-to-speech algorithms within MITalk, and in 1982 he developed Klattalk, his own real-time lab-based text to speech system. He also produced a definitive history of speech devices with includes a collection of recordings from all the devices developed throughout the twentieth century.

TSI devoted considerable effort to make an improved real-time version, by 1980 producing five working prototypes on custom LSI VTM chips. In 1980, Telesensory esablished a separate Speech Systems Division to pursue industrial and commercial applications of its speech synthesis technologies.

In 1982, Speech Plus Inc. was formed when Telesensory sold its text to speech and other speech technologies to the newly formed company, with James Bliss as director. Their first product, the Speech Plus Prose 2000, was released the same year, retailing at $3500. It was a high quality unlimited vocabulary text to speech system on a single printed circuit board.

During a visit to CERN in the summer of 1985, Professor Hawking contracted pneumonia. It was so serious that Jane Hawking, his wife, was asked if his life support should be terminated. She refused, but the consequence was a tracheotomy which removed what speech he had left.

Professor Hawking was given the Equalizer software keyboard and his Speech Plus card by Walt Waltosz from Words Plus in late 1985; who had written Equalizer for his disabled mother-in-law. It allowed him to write at 10 to 15 words per minute and then send it to the voice synthesizer to be spoken. He also tried out voices by DECtalk and Votrax, but much preferred the one by Speech Plus. It did have the side effect of giving him an American voice.

Professor Hawking wrote, "I had an Apple II which had a floppy disk drive. I think that was my first Equalizer. I had bought a Commodore PET computer in 1979 with 16kB on which I wrote a bubble collision program. PET was obsolete by 1983, and I got a BBC Micro on which Robert Hawking and I wrote a machine language program to allow me to write using two joysticks. One to highlight the letters and the other to select." David Mason, husband of one of Stephen's nurses, Elaine Mason, adapted this desktop system to a portable system attached to Stephen's wheelchair. Now his voice could go with him wherever he went.

In 1988, Professor Hawking visited Speech Plus in California while publicizing his recently launched book "A Brief History of Time" (He started writing it in 1982). He was given an updated card, his current CallText 5010 model, but he didn't like the voice and asked them to replace the 1988 EPROMS with the 1986 version. The cards were designed for telephone exchanges and Professor Hawking has said "I used to be able to dial and answer calls but I can't now."

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Peter Benie <peterb@chiark.greenend.org.uk>