Xbox One will launch in 13 countries in November 2013, however not all countries will get access to "Xbox On" voice command at launch. As per the details revealed by Microsoft representative, only five countries will have access to "Xbox On" voice command, "United States, United Kingdom, Canada, France and Germany".
In addition to this, Microsoft representative also stated that voice controls will be available in 10 of 13 launch regions.
Microsoft was forced to clarified these things because a text on official Xbox One Product Page (right at the bottom) reads something like this: "Xbox voice commands will not be available in all markets on the product release date."
Here is what Microsoft representative told GameSpot.
"Our vision is to bring conversational voice control and voice search to every country where we sell Xbox,"
"At Xbox One launch, we will offer voice control in 10 of our 13 launch markets, with eight total languages: English US, English UK, French, Spanish MX, Spanish ES, Italian, German, and Portuguese. There will be some voice experience variations in different markets at launch; the 'Xbox On' voice command will only be available in five markets (United States, United Kingdom, Canada, France, and Germany) and will come to others in the near future."