Stephen Hawking's speech machine was a text-to-speech system designed to produce synthesized speech from text input. The system was developed by a team of engineers at Cambridge University in the 1980s, led by Professor Hawking and Dr Peter Nollinger. The machine used a form of artificial intelligence known as rule-based synthesis to convert text into speech, and was capable of producing clear and understandable speech even when the input text contained errors or was incomplete.
The system consisted of two main parts: a rules engine that converted text into phonemes (the basic units of sound in spoken language), and a synthesizer that generated the actual sounds from the phonemes. The rules engine could be configured to generate different types of speech, depending on the needs of the user. For example, it could be configured to speak with an American or British accent, or to emphasize certain words or phrases.
The synthesizer component of the system was based on technology developed by Digital Equipment Corporation (DEC) in the 1970s. It converts phonemes into digital signals that are then sent to a loudspeaker. The sound quality produced by the DEC synthesizer is quite good, although it is not identical to human speech.
The first version of Stephen Hawking's speech machine was built in 1986, and he used it until his death in 2018. In 1996, he switched to using a more advanced version of the system that used software instead of hardware for processing text input. This allowed him to use any computer with internet access as his speech machine, rather than being limited to using specialized hardware.
In 2014, Professor Hawking unveiled an updated version of his speech machine that uses voice recognition software instead of keyboard input. This allows him much greater freedom and flexibility in how he communicates; for example, he can now dictate emails and articles directly without having to type them out first on a keyboard