Then why on every single video showing the Wii U Chat, is it silent? and why does it say here: http://www.nintendo....software/#/chat that you 'communicate through handwriting" and it doesn't mention anything to do with the mic.
Because it's obvious that it uses the GamePad's mic.
If it didn't, they would've made a separate mic attachement and under the Wii U chat section, it would say "Wii U Mic needed. Sold seperately".