Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech computer or speech synthesizer, and can be implemented in software or hardware products. Stephen Hawking began using a text-to-speech technology called Perfect Paul after he lost his ability to speak. Hawking was able to communicate despite his paralyzing neurodegenerative disease, however, Perfect Paul wasn’t actually perfect. It not only made Hawking sound like a robot; it was missing his British accent. In adopting a synthetic voice, Hawking relinquished the characteristics that made his voice distinctly his.
“If your voice sounds like an ATM or an Alexa device, how can you take ownership over that prosthesis? It doesn’t feel like an extension of you anymore,” says Rupal Patel, a professor of communication sciences and disorders at Northeastern University. This served as the basis for Patel, who then founded a company VocaliD that creates custom voices for people who either can’t speak or are at risk of losing their voices in the future.
VocaliD can create vocal legacies, which are recordings that preserve the voice of someone who might need text-to-speech assistance later in life. That way, the person’s own voice can be used for generated speech in the future. As for people who have never been able to speak because of conditions such as cerebral palsy or severe autism, VocaliD can use nonverbal sounds these people make to create voices that reflect the vowel sounds, melody and pitch of what they would sound like if they could speak. Patel says, “They can’t speak, but they can still do other things with their voice”. Those nonverbal sounds are then blended with recordings made by a voice donor, who matches the age and gender of the person who needs the voice.
“Voice changes are often the first signs of vocal or neurological disorders,” she says. “Speech is such a fine-grained movement that even small changes can show up as symptoms early on before someone loses full motor control.” She, thus, highlights that as voice analysis technology becomes more advanced, doctors can use our voices to track changes in our health.