Aptech has extensive experience of supporting dyslexic people, and its software, Keystone, offers an easy and powerful way to work in Windows, either on its own or with voice recognition software.

A crucial part is the text-to-speech feature, which provides British English pronunciation which both sounds natural and interprets context correctly, for instance, “His prescription was invalid although he was an invalid.”

You can request text on the screen to be read by paragraph, sentence, line, word or character. There are also settings for magnification, zoom and colour preference. This makes Keystone excellent for the visually handicapped, and also for those with physical handicaps who need to use input devices such as single-switches.

Keystone automatically checks for homophones such as four, for and fore and provides a contextual phrase to help the user to distinguish and learn them. It is ideal for dyslexics with DragonDictate voice recognition. This allows hands-free text input and Windows control, with Keystone helping to check spelling and punctuation in the resulting text.

There is a series of Keystone products, whose prices and system requirements vary according to which software it complements and whether voice recognition is needed; all are for Windows PCs.

Drawing on five years’ experience of Keystone with DragonDictate, Aptech is about to release KeySpell, which is much more than a spelling checker. KeySpell can stand alone but, for maximum effect, it has been designed to work with voice recognition, including the new generation of continuous products such as Dragon NaturallySpeaking and IBM ViaVoice.

Unlike a conventional spelling checker, KeySpell provides sensible alternatives to words spelled phonetically. For example, typing “acomdashun” will produce “accommodation”, “lfant” will yield “elephant”, and so forth. A really neat option allows you to hear each word spoken in context, in a meaningful sentence.

KeySpell also checks words which, although present in its dictionary, may have been used out of context. The sentence “It eye dent if eyes miss steaks aye can knot sea” contains 11 words of which nine are wrong, but none was queried by my spellchecker.

KeySpell can be set either to check each word as it is input, or to defer checking until the user is ready. Instead of a long scrolling list, which can look off-putting, it displays possible words in a grid of nine words, with alternatives based on context, phonetics and user history.

* Keystone prices range from Pounds 150 to Pounds 495, while KeySpell costs Pounds 99. Prices exclude VAT, but Aptech can zero rate special needs software