How does Stephen Hawking Talk

One of the most brilliant theoretical physicists of the century, Professor Stephen Hawking is known for his pioneering research that helped in understanding black holes and his contributions to quantum gravity and cosmology. His bestseller book 'A Brief History of Time' written for the layman first introduced me to the man and his work. Professor Hawking unfortunately suffers from a rare neuromuscular dystrophy disease, closely related to Amyotropic Lateral Sclerosis (ALS), that has confined him to the wheelchair, due to bodily paralysis. He lost his ability to communicate due to the progression of the disease. His public appearances and speeches always make people curious as to how does Stephen Hawking talk in spite of losing his voice? I provide an answer to this question and in the process, explain how technology has helped people with voice disabilities to communicate with the world.

How Does Stephen Hawking Communicate With People?

The young Stephen Hawking was diagnosed with motor neuron disease when he was 21 and since then with the progression of the disease, which slowly melts away the neurons of the body, lost the ability to use his arms and legs. His voice also became slurred over time as he lost muscle control. In 1985, tragedy struck when he was diagnosed with pneumonia which threatened his already limited respiratory capacity. The only way out was to conduct a tracheotomy. It is the surgical opening of an airway, directly through an incision in the windpipe (trachea). As a result of this procedure, he completely lost his ability to speak. Today he is completely paralyzed below the neck but continues his work from the confines of a wheelchair enabled by technological aids.

You must be wondering how Stephen Hawking can talk, despite having a tracheotomy. That is thanks to the advanced speech synthesizer that he uses. The voice you hear as Professor Hawking's is actually a computer generated voice, created by the speech synthesizer! For a long time, since his speech started becoming slurred, he used the DECtalk DTCO1 voice synthesizer, which was a revolutionary device developed from the text to speech technology based on an algorithm written by MIT student Dennis Klatt in the early 1980s. Professor Hawking was one of the very few people who got to use this device first.

How do these voice synthesizers work? They contain a predictive text program from which the person using it can select words to construct sentences. In Professor Hawking's case, he uses his cheek for entering words and all of his speeches and articles are created this way. It takes a lot of time to enter the words and create his speeches which are then voiced by the synthesizer using advanced computer equipment attached to his wheelchair.

Though speeches are made possible through advanced preparation and assistance, direct interaction is understandably difficult and time-consuming for Professor Hawking. He had been using the DECtalk DTCO1 voice synthesizer for a long time, even after its production was stopped, as he had grown fond of the American English accented voice. Now he has switched on to the NeoSpeech's VoiceText speech synthesizer. It is incredible how the great physicist has continued with his work and not let the physical disabilities be stumbling blocks.

I think Professor Hawking's indomitable spirit in overcoming the motor neuron disease and doing great work despite his disability is truly inspiring!