With Windows Phone 8.1 only five weeks out, there’s not too much left to revealed, except one big feature: Cortana.

The digital voice assistant to rival Apple’s Siri and Google’s Now service is expected to premier with Windows Phone 8.1, and while a few facts have leaked out so far, the Verge has now gone into more detail about Cortana, including its Notebook core.

According to the Verge's Tom Warren, Cortana will have a ‘Notebook feature’ that stores “location data, behaviors, personal information, reminders, and contact information”, but only as the user allows. This is to ensure that privacy takes priority over efficiency of the assistant, meaning Cortana won’t collect, store or use information about you without your consent. Indeed, information can reportedly be edited or even deleted later by the user.

That’s certainly throwing down the gauntlet against Google, who don’t have such restrictions or control on Android.

Other details about Cortana confirm our earlier report about it having a “personality”, represented as a bouncing ball with emotions to reflect current inquiries. From our earlier report, we heard Cortana described like this:

“The personality of Cortana is currently represented by a circle graphic that expresses what it's doing (searching, identifying music à la the current Bing music listener built into Windows Phone, etc.) by various animations like spinning, flipping, etc.  …more animations [have] come in over time, and the color is based on your theme color.”

Regarding some behavior, the Verge notes that Cortana will offer “guidance on weather, stocks, directions, appointments, and music that’s contextual based on location and other data”. Likewise, it is also confirmed that Cortana will act upon incoming messages, email and other alerts, offering to lend assistance.  This feature was described to us earlier by a source familiar with Microsoft’s plans:

“For example, let's say I send you an SMS that says like "Want to get dinner tomorrow in Seattle?" You'll see parts of that text message underlined. Click that and you'll be able to instantly enter the info into your calendar with some of those fields already populated. So it would fill "Seattle" as the location, if I had said a time it will already have the time there.”

Finally, the Verge also reveals a very useful feature for your favorite acquaintances

“An "inner circle" of contacts will allow Cortana to manage notifications and phone calls during "quiet hours" when notifications are muted.”

Powered by Bing and Foursquare – amongst the initial services – Cortana as introduced in April will be just the beginning of this new Microsoft tool. From that point, Redmond will have to expand Cortana to other areas, including Windows 8, Xbox, in addition to adding services or improving contextual search and behaviors.

Regarding the name, currently the beta SDK only refers to the function as ‘Cortana’. But as unearthed in the MUI strings for voice commands, users will actually be able to name their voice assistant, making the matter a bit moot for the average consumer.

Windows Phone 8.1 will reportedly be revealed during Build on April 2.

Source: The Verge