Prosaically dubbed "Voice," the app's addition is powered by a combination of Nuance software and DirecTV's own, in-house proprietary tech. And thanks to the old pros at Nuance, the app does a great job of responding quickly and accurately to your commands. But rather than being integrated into the original UI (which remains mostly unchanged), Voice is tacked on as an entirely separate screen. Activating Voice turns your phone into one big, blue microphone, so you're either manually tapping through or you're using Voice—never both.
At this point, though, the app's functionality is limited as far voice control goes. You're stuck with vocalizing most of the same step by step instructions you'd be inputing with a normal remote. Granted, saying the title of a show, for instance, is far less tedious than seeking it out letter by letter, but it still isn't quite able to handle the fully natural speech you'd be inclined towards. No tapping open the app and absentmindedly telling it to record all new episodes of Breaking Bad; you'll have to go through search and then tell it what you want to do—a minor but noticeable inconvenience.
Voice is still in its infancy, though, and it's one of the first apps from a television provider that employs voice recognition technology at this level. You should be seeing Voice come to DirecTV mobile in the App Store and Google Play Store sometime this summer, with tablet versions surely soon to follow.
Voice Control Is Coming to DirecTV's Smartphone App