Those studios planning to integrate voice chat into their Nintendo Wii U games should be aware that there are certain caveats -- such as the fact that the GamePad's microphone cannot be used for this purpose.
Nintendo talked to Kotaku about the use of in-game voice chat, stating that the likes of Assassin's Creed 3, Call of Duty: Black Ops 2 and Mass Effect 3 will utilize the functionality.
However, gamers will not be able to talk to each other via the Wii U GamePad's base features, but rather, it will be necessary to purchase a licensed third-party headset from either Turtle Beach or Mad Catz, to plug into the GamePad jack.
When it comes to the console's Pro Controller, it's a different story altogether, as the controller does not have a jack for a headset. Instead, gamers will be required to connect their headset to their GamePad, and leave the GamePad lying within range, cable-permitting.
Notably, there is currently no wireless headset available for the Wii U. A rep for Turtle Beach did note that the Wii U supports Bluetooth and can pair with its own accessories, and Nintendo says that this may be a possibility in the future.
Gamasutra contacted Nintendo to confirm that voice-chat via the GamePad's microphone is still available for actions outside of the games (in Miiverse, for example), and was told, "We will announce details on Voice Chat and other functionalities of Wii U at a later date."