By Liz Seward
Science reporter, York
Computers could mimic human speech so perfectly that vocal terrorism could be a new threat in 10-15 years' time, scientists suggest.
Will it be more difficult to trust the bank manager of the future?
In the future, it may be possible to mimic someone's voice exactly after recording just one sentence.
Such technologies would pose a danger if it were not possible to verify who was speaking, researchers believe.
Scientists were predicting the future at the British Association (BA) Festival of Science in York.
Dr David Howard from the University of York said: "The reason things are changing is because no longer are we using an acoustic model proposed in the 1950s."
New methods of creating computerised speech use models of a vocal tract to create a realistic sound, replacing the existing technique of copying sounds.
"We are beginning to simulate virtual vocal tracts in the computer," said Dr Howard.
"When we simulate this in the computer, which we are beginning to do, we begin to get sounds that musicians describe as organic or more natural.
"If we get to the point where we are synthesising the actual shape of somebody('s vocal tract) based on analysis of their speech, then the speech we are producing should sound and look like the actual person."
Worrying scenarios envisaged by the researchers included a phone call, apparently from your bank manager, requesting you to confirm details of your account.
If the call actually came from a computer able to mimic the bank manager's voice flawlessly, your account could then be emptied by the people operating the computer.
New technologies involve creating a synthesised human windpipe
Fraudsters are already making this kind of call; but the new technology could make them much more convincing.
It might become easier to make prank calls as well.
The terrorism aspect would come in if the technology were used for more malicious purposes, such as someone taking over a communications network for a country and broadcasting a speech apparently from the country's leader.
"This gives rise to this notion of what I call vocal terrorism as a possible scenario in the future, which I'm suggesting one should be thinking about now and not thinking about when it happens.
"It's not scaremongering; it's trying to say to people, 'we have to think about these things'," he said.
Dr Howard made these predictions to challenge the view of young people on social responsibility.