I expect we will see over the next 12 to 24 months this technology will become relatively ubiquitous. It's like E-mail, which was around for years before people started using it. Now that we have computers powerful enough to do it, everyone uses it. The technology is far from perfect. One key principle is that the systems should learn as they go.
Accuracy continues to be the most important parameter, because it's critical for acceptance.
Another obstacle is natural-language understanding. It's not a yes or no feature, but something that will get built in gradually. It makes sense, for example, that speech technology should move into Web browsers. But speech-enabled browsers won't be able to understand the subtleties of a request for another couple of decades. I expect we'll see a translating telephone, for example.