What is frustrating about this, says Dr Kristensson, is that more often than not the correct strings of words were recognised, but rejected by the speech-recognition program on statistical grounds.

ECONOMIST: Monitor

The prototype uses an open-source speech-recognition program called Pocket Sphinx, developed at Carnegie Mellon University, in Pittsburgh, but Dr Kristensson reckons it would be easy to apply the same approach to commercially available programs like Nuance's Dragon.

ECONOMIST: Monitor