I got a new iPad 3 - voice to text worked for about a day, then hasn't worked since - for 3 or 4 days now. The purple dots just wiggle a while the go away. I've tried killing all the apps and rebooting.
Apparently this is not an uncommon problem: http://www.google.com/search?hl=en&s...iw=753&bih=905
Interstingly my iPhone 4S was doing the same thing. So I tried the advice in the thread above - close all the apps and make a Siri request. Siri worked, and immediately after voice to text started working, after being down for days. Unfortunately no Siri on iPad.