However, the software being used also has to be capable of producing speech output. For example, a word-processor will have to include a speech option or be used alongside a separate speech utility program such as Text Help . Specialist software is also available to translate the entire output of the computer into speech for users with visual difficulties. Using and setting up this software requires a considerable degree of training and skill. For example, it would be useless to a blind user to have the computer read the entire screen display at regular intervals as they will require specialist feedback i.e., the software will be able to recognise the appearance of a window with information and will only speak that information when required.
Computers are capable of producing two types of speech - digitised and synthetic.
Digitised - real speech sounds are recorded and turned into digital information which can then be stored and replayed, in a similar way to audio CDs. Synthetic - speech or sounds created by the software. A speech synthesiser will turn text into speech by applying the standard rules of pronunciation. Synthesisers are becoming cleverer and are able to make good sense of text, providing appropriate pauses and inflections etc. resulting in speech which is becoming more natural and less robotic. Speech synthesis is necessary to read back the work done by a child using a word-processor, or to help a visually impaired or blind user by reading back everything that they have written.