PS4 video guide shows you how to use voice commands on the console 

While PlayStation 4 may have limited voice controls at launch, you can still do a few things with your PS Camera. Voice commands include launching a game by saying its title, then "start" you can also log into the system and go back to the home screen by using the obvious commands. You can also tell it to take a screenshot and turn on the console or log out. Voice commands so far work in English, Spanish, Italian, French, German, and Japanese. More functionality will be released over time. Voice commands are demonstrated in the PlayStation Access video below. PS4 is out Friday in Europe.