There has been a long running debate about artificial intelligence, with a large contingent of computer scientists always proclaiming that computers "smarter than humans" is only five years away. And there has been a small but persistent group of computer scientists who have insisted computers will never be "smarter than humans."
Here is an interesting read on speech recognition and why it has never caught on. The "computers will be smarter than humans" crowd will scoff at this and insist that speech recognition has little to do with artificial intelligence, but if you can't write a program to recognize speech, how are you going to write a program to make a computer "smarter" than a human? Our ability to hear and cognitively process the spoken work is absolutely staggering, and after thirty plus years of attempts to duplicate it, speech recognition is still lousy. Spend just a few minutes on the phone with one of those voice mail speech recognition systems (...say Customer service.... "Cus-tom-er ser-vice"...I'm sorry, I did not understand, say Customer service..."Cuuuusssttttommmer Seerrrrvvviccce"....I'm sorry, I did not understand, returning to Main Menu...) knows that speech recognition stinks.
Update (10/2011)
Apple's Siri voice recognition app on the iPhone 4S shatters whatever any of us previously thought about voice recognition. Siri does an incredible job of taking dictation and processing routine smartphone requests.