Sheila Grant has never been able to speak but last month she addressed hundreds of delegates at a Canadian conference using a new speech aid developed in Dundee.
Ms Grant, who has cerebral palsy and is in a wheelchair, demonstrated the computer-based conversation aid at the Vancouver conference of the International Society for Augmentative and Alternative Communication.
The TALK system has been developed by researchers at Dundee University's psychology department in collaboration with the university's MicroCentre and colleagues at the University of Abertay Dundee. It links a laptop computer and speech synthesiser to allow people without speech to achieve something much closer to ordinary speech than is possible through traditional systems, by using banks of segments of conversation.
"By preloading the content of anticipated conversations in what might be thought of as 'conversational chunks', users can respond relatively quickly in a 'live' situation," explains psychologist John Todman.
"Instead of having to key in each reply or comment, a laborious process which interrupts the normal flow of conversation, they can tap into their personal bank of preloaded 'chat chunks', thereby keeping the flow going."
The traditional lightwriter, in which sentences are typed in key by key, averages around seven words a minutes, whereas TALK has a rate of about 60 words a minute, compared to normal conversational speed of 140 to 200 words.
TALK has had to overcome two major problems: how to respond when the conversation took an unexpected turn, and finding the appropriate response quickly.
The system deals with the first of these by including a bank of general comments, such as "That's a good question" and "What a drag", and tackles the second through the organisation of the content, reflecting the way in which topics tend to shift in small steps from, for example, "me" to "you", and between the past, present and future.
"If the user shared an interest with a particular friend in, say, science fiction, she could shift the conversation very easily from talk about what authors she likes, why she likes them, and which books first got her interested to which books interest her friend, what her friend is planning to read next, and so on," said Dr Todman.
Ms Grant's 75-minute presentation included answering questions. "To be able to engage in a free-flowing discussion, and to do this without long pauses to type in responses, is a remarkable achievement for a non-speaking person," added Dr Todman.