There is clearly a knowledge graph coupled with this in addition to the speech recognition. Sorry, "meaning" recognition. I feel like there is an opportunity to connect the deep knowledge graph of Wolfram Alpha -- or that maybe Wolfram missed the ball by not connecting their graph in a more usable way.
I wonder if it is based on Freebase.com knowledge graph, which Google discontinued last month. http://www.freebase.com/ (and recently IBM has bought Blekko web search and knowledge graph engine as a replacement for Freebase to power their IBM Watson)
