Screenshot by Nick Statt/CNET

Microsoft has introduced its long-awaited answer to Siri and Google Now and it is indeed called Cortana, named after the artificial intelligence character from the company's flagship video game franchise Halo.

Microsoft's Joe Belfiore, head of Windows Phone product and design, unveiled the personal assistant software for Windows Phone onstage at the company's annual Build conference in San Francisco. It is being launched in beta for Windows Phone 8.1 -- rolling out over the next few months -- and will expand beyond the US to the UK and other countries over time.

"We think Cortana is the most personal digital assistant," Belfiore said.

Cortana is powered by Bing, and can perform many of the functions one has come to expect from artificial intelligence-style assistants, such as setting reminders and powering vocal updates to one's calendar.

The voice behind the software was reported back in January to be Jen Taylor, the voice actress of the character from the Halo series. Microsoft declined to comment back then on Taylor's involvement, but Cortana sounded awfully like Taylor in the version unveiled today.

CNET has reached out to Microsoft regarding Taylor and Cortana and will update this story when we hear back.

During the demo, Belfiore also showed off Cortana's ability to respond to dynamic questions about weather, sport scores, and search engine queries like food calorie counts.

"What's the story of the next Halo game?" Belfiore asked in jest, clearly setting up an example of the oft-lampooned Siri exchanges that lead to Apple's software spitting out a comical pseudo-human response.

Cortana responded, "I'm quite certain you don't have proper security clearance for that information."

Screenshot by Nick Statt/CNET

The assistant appeared to take a stumble, however, when Belfiore attempted to get Cortana to convert temperatures. From Fahrenheit to Celsius worked smoothly, but from there to Kelvin -- worded as "what about Kelvin?" -- kept pushing Cortana back to Celsius, an interesting display of the assistant's limitations in understanding more colloquially-worded follow-up questions.

Belfiore also introduced a differentiated element to Cortana: the ability to ask less factual, and more socially applicable questions. For example, Belfiore set a reminder to ask his sister about her new dog, meaning whenever he is texting her or talking to her on the phone, Cortana will know to fire off the reminder.

Cortana will also extend beyond Windows Phone native apps. "We needed all of you to help make her better and better," he noted, explaining that the assistant can be plugged into third-party apps.

He showed off three such apps -- Skype, Hulu, and Facebook. Cortana was able -- through voice commands -- to start a Skype call, add a video to a Hulu Plus queue, and launch a specific friend's Facebook page.

James Martin/CNET

It's unclear how Cortana, currently in beta and not yet available to consumers, will shape up against Google Now or Siri. Both of those pieces of software have both had years of experience taking in voice commands and improving itself through natural language processing.

For now, Cortana will cruise happily on its cool factor, enticing Halo fans and comforting those that have found the unfamiliar voice of Apple's assistant to be a bit creepy compared with something gamers have grown accustomed to hearing in their ears as they play.

Read more about the announcement on CNET's live blog.