After years of promise, voice recognition is at last becoming a significant method of using computers and accessing the Internet. Why now, and what difference does it make ? Peter Day talks to the companies at the forefront of developments in the field (including Massachusetts-based Nuance, one of the largest makers of voice recognition technology), and asks whether our relationship with machines will change once we have the ability to talk to them. \nProducer: Neil Koenig\nEditor: Jeremy Skeet