Apple has included limited voice control functionality in the iPhone since the debut of the iPhone 3GS, but the company's plans for voice control in iOS 5 are reportedly far broader in application according to 9to5 Mac. While no such feature was announced at WWDC and it has yet to show up in the iOS 5 betas, 9to5's sources claim Apple's test units are already testing out an "Assistant" feature meant to introduce widespread speech-to-text functionality in iOS 5.
Those of you who have used Siri or the