It has been advertised far and wide that Cortana has to be specifically tailored to each region and country before it is made available for that region and/or country. Cortana is only in a few select markets right now, but will be expanding as Microsoft is able to tailor it to fit in with the needs of each region. After all, Cortana is not just something that regurgitates information like Siri or Google Now. She is a Personal Assistant, and part of that personal has to be worked in with the cultures of each region.