The Xbox One's ability to listen to your sultry, sensuous voice and translate those mouth noises into a command to watch New Girl on Netflix will only function in five markets at launch. Specifically, those markets are the United States, Canada, United Kingdom, France and Germany. This means that Xbox Ones sold in Australia, Austria, Brazil, Ireland, Italy, Mexico, Spain and New Zealand will be without this functionality on launch.
The news was mentioned at the very bottom of this lengthy Xbox One overview on Xbox.com. No further information was given beyond the fact that "Xbox voice commands will not be available in all markets on the product release date," so exactly when voice commands will make it to the remaining launch markets is anyone's guess. Earlier this month, Microsoft scaled the Xbox One's launch from 21 to 13 territories, with later reports citing Kinect localization as the main reason for this delay.