Xbox One voice commands will only work fully in some launch countries, languages@ 2013/08/30
That said, some voice features -- like the "Xbox On" command -- will not be available everywhere at the start, with only the US, UK, Canada, France, and Germany set to receive them out of the gate. As Penello explains it, users will select their language first, and then get a list of countries it's supported in. Confused? A more thorough explanation is coming to the Xbox website at some point, and Kinect's supported languages are expected to grow with updates after the system launches -- whenever that launch is.