In computing, Cortana is an intelligent personal assistant on Windows Phone 8.1, Microsoft Band, The name of the software comes from Cortana, the artificial intelligence character in Microsoft's Halo video game series, with Jen Taylor, the character's voice actress, returning to voice the personal assistant's US-specific version. Cortana was demonstrated for the first time at the Microsoft BUILD Developer Conference (April 2–4, 2014) in San Francisco. It has been launched as a key ingredient of Microsoft's planned "makeover" of the future operating systems for Windows Phone and Windows. As of 2015 it is available to all users of Windows Phone 8.1 in the United States, China, and the United Kingdom. Users in India, Canada and Australia can also choose to opt-in to the beta for the American English version of Cortana as of August 2014. Microsoft expects Cortana to be available globally by early 2015.