Synthetic speech is artificial human speech, which is produced by a computer.
How is synthetic speech used by blind and partially sighted people?
Many people will have experienced synthetic speech, possibly without even knowing it. Common applications used in the wider world include railway station announcements and telephone systems. Synthetic speech is also available on products, such as mobile phones or music players which can "read" out menu systems or portions of text.
As many blind and partially sighted people access information through audio, synthetic speech has a wide range of applications. These range from simple talking products (such as clocks and thermometers), to reading materials (such as books) to access technology such as screen readers which allow blind and partially sighted people to access computers. Screen reading software on computers and ebooks are key uses of synthetic speech for blind and partially sighted people.
What are the benefits of synthetic speech?
- Speed of access. Recording information via human narrators is time consuming. Synthetic speech can be produced very quickly from an electronic text file, meaning synthetic speech may enable quicker access to information.
- Privacy. For confidential information such as financial statements or medical information, synthetic speech offers a means of access without someone else (a human narrator, friend or family member) having to relay the information.
- Speed of delivery. Synthetic voices are designed to be clear at speed, and can be sped up beyond the rate at which a human could speak.
What are the disadvantages of synthetic speech?
- Articulation. While technology is always advancing, it is fair to say that even the best synthetic voices don't sound quite human. Some users complain about robotic voices, poor pronounciation and strange intonation.
- Intelligence. Synthetic voices cannot pick up on the context of the information they are reading. When used for audio books, some users dislike the lack of human input, such as humour, accents and intonation. The importance of such features is likely to vary depending on what the synthetic speech is being used for.
- Attention. Some users find synthetic speech more difficult to listen to and find they have to pay more attention to it compared to human speech. This could affect reading performance, although it is commonly reported that people get used to listening to synthetic speech over time.