When computers speak, hear, and understand

"OPEN the pod bay doors, HAL." The HAL9000 computer responsible for the Discovery spacecraft's mission to Jupiter in the classic 1968 movie 2001: A Space Odyssey by Stanley Kubrick and Arthur C. Clarke was more than reluctant to oblige despite the immediate risk to astronaut Dave Bowman. Still, almost two generations of science fiction and movie fans have been raised with the concept of a computer that not only understands every nuance and word in the spoken language but also reads lips, generates flawless speech, and thinks for itself. Looking toward the future of speech technology, science fiction offers the prospect of both positive and negative developments.