Predictive packages run alongside word processors. A box containing a small group of words is displayed on the screen. As you type, the words in the prediction box change to the most likely options, based on the letters you have typed and the words you have already used.

If you do not want one of the first group of words, type the second letter and up comes a new list, and so on. Press the appropriate key and the whole word is inserted into the text. The more often you choose a word, the higher up the list it goes.

PAL (Predictive Adaptive Lexicon) was one of the first prediction packages. It was the brainchild of staff at Dundee University and was designed to make text input easier for physically disabled students. Some university students with cerebral palsy type at only 15 keystrokes per minute so the little bit of text you have read so far would have taken about an hour to produce. With a predictive package they can get more written before they run out of time or energy.

PAL was greeted with great acclaim and staff working with dyslexic students thought it might help their learners. One of the early problems with PAL was that every word you typed went into its dictionary, whether it was correctly spelt or not. To get round this problem, you needed to edit the dictionary regularly. Teachers found this too time consuming.

Now you can choose whether or not words are entered and you can also SpellPAL, an add-on facility at Pounds 24.99, which will double-check spellings and offer phonetic alternatives.

This means that it realises that “fzx” might well be “physics” while conventional spell-checkers suggest “fax”, “fix” and “fox”.

The bad news about PAL is that it is DOS-based and there are no plans for a Windows version. However, PAL and its accompanying word processor, PALSTAR, will run on an Acorn Archimedes under the PC emulator.

But for those of you who are not using DOS-based machines, here are some alternatives. For the PC, there is Prophet from the ACE Centre, a snip at Pounds 60. Prophet has been used very successfully with the Switch Access to Windows program so that switch users click on a letter in the grid and up comes a series of predictions.

Recently I have been writing a lot about mental health issues, an area which seems to specialise in long words - psychological, psychiatric, psychotic and psychiatrist occur regularly. I type “ps” and choose from the list. For a learner with limited reading, the teacher can load in a dictionary of words on a particular topic. Then, as the student writes, only the words he or she needs will appear. Prophet works quite well with Windows 95 and will be fully compatible by the autumn.

Co:Writer is a sophisticated predictive package for Apple Macs. It was used as part of the NCET’s Focus on Deaf People project with a group of further education colleges. Lesley, a deaf student from Bolton, used it to produce some writing for her Wordpower certificate. Her tutor describes the experience: “The group had been talking about a deaf American racing driver who trains disabled deaf people in driving. Lesley was really interested in this session and she could sign about it fluently in BSL but she didn’t seem confident about writing it.

“I loaded Co:Writer and ClarisWorks for her and explained about the ‘wake up’ key. She started typing and was at first perturbed by the words which appeared underneath. Then she realised they could help with spellings. She wasn’t putting in the capitals at the beginnings of sentences or days of the week and, when the computer corrected these automatically, it drew her attention to them. Lesley was fascinated by the way that the predictions gradually began to match her thoughts. She wanted to know how the computer could do this.”

My tests on PenFriend, a predictive package for Acorn machines, coincided with an Open Day at the NCET, so it seemed like a good opportunity to get a group of visitors to put the software through its paces. The testers were Louise, Natalie and Kirsty from Trinity School in Leamington Spa. None of them had used a predictive word processor before but they liked not having to type every letter.

Natalie’s first sentence, “My favourite colour is purple”, wasn’t a great success. She only saved three keystrokes on the sentence but she was impressed when favourite and colour appeared on the lists next time round. Louise saved seven keystrokes on her sentence, “My cat is called Sam”, but Kirsty only saved three on “I can see a boat”.

Of course, to get the best from predictive word processors, you need to work with them on a regular basis so they learn the words you use and predict more accurately what you are likely to say.

While this is not the most sophisticated predictive word processor and does not work on a grammatical or syntactical model, it is excellent value for money at Pounds 25 per single user.

Before you buy a predictive package, ask the following questions: will it put in a space automatically after each word? Does it put a capital letter after a full stop? Can you set a minimum length for predicted words? Can you alter the position of the window on the screen? Can you have a different dictionary for each user or topic?

Future generations will take predictive packages for granted. They will probably be amazed at the thought that at the end of the 20th century we still had to type each letter of every single word we wanted to write.

* PAL plus PALSTAR Pounds 54.99; SpellPAL Pounds 49.99, together Pounds 89.99. Lander Software, 1 Atlantic Quay, Glasgow G2 5EJ. Freefone: 0800 403040

Prophet Pounds 60. ACE Centre, Ormerod School, Wayneflete Road, Headington, Oxford OX3 8DD Tel: 01865 63508

Co:Writer Pounds 203. Don Johnston Software, 18 Clarendon Court, Calver Road, Winwick Quay, Warrington WA2 8QP. Tel: 01925 241642

PenFriend Pounds 25. SEMERC,1 Broadbent Road, Watersheddings, Oldham OL1 4LB. Tel: 0161 627 4469