CNet picked up a small update on the Xbox One product page noting that only certain territories would get voice commands at launch.
It's a not dissimilar situation to when the Kinect itself first launched in Australia and New Zealand - apparently our chaotic, indecipherable accents are just too much for the hardware to handle. Initially, at least.
Microsoft's recent delay of the Xbox One in Eastern European countries was also blamed on localisation issues, but it would seem that these problems were specifically related to the text on the dashboard, considering it's still set to be released here.
Territories which will get voice commands at launch are the US, UK, Canada, France and Germany.