Microsoft unveils Cortana with Windows Phone 8.1

Background

Build is where Microsoft presents its Windows plans to developers, and the 2014 edition was held in San Francisco ^[1]. By that point, a digital assistant — software you can ask a question in ordinary language, which answers it and sometimes acts on the answer — had become one of the features against which phone platforms were compared. Windows Phone 8.1 was the next major release of Microsoft's phone operating system, and it arrived with an assistant attached.

What was announced

On 2 April 2014, Microsoft unveiled Windows Phone 8.1 at Build and introduced Cortana ^[1]. Microsoft described Cortana as "the world's first truly personal digital assistant", and gave it a persona inspired by a character from the game Halo ^[1]. The persona was part of the pitch: a named character with a voice and a manner, rather than an unnamed recogniser behind a microphone button. That framing set expectations — the assistant was presented as something a user would deal with repeatedly and would get to know.

How it worked

Cortana is powered by Bing ^[1]. Microsoft said the assistant improves over time by asking questions based on user behaviour and by checking in before assuming what a user is interested in ^[1]. What it learns is kept in a Cortana Notebook, which the company said makes the assistant proactive during the day ^[2]. Proactive here means the opposite of waiting for a command: the assistant is meant to bring things up on its own, drawing on what the Notebook holds.

Developer access

The same event brought a developer API for Cortana, alongside enhancements to the Speech API ^[2]. An API is the interface through which one program calls another; opening one for the assistant at launch meant that developers outside Microsoft could build on it rather than leaving it closed to the company's own features.

The rest of the update

Windows Phone 8.1 also added an Action Center, a single place that collects notifications from any app, and the Word Flow keyboard ^[2]. Neither is the headline of the release, but both are the sort of thing users touch every day.

Rollout

Microsoft said Cortana would launch shortly in the United States as a beta — an early release handed to users for testing — reach the U.K. and China in the second half of 2014, and come to other countries in 2015 ^[1]. Windows Phone 8.1 itself was to roll out to existing Windows Phone 8 users over the following months and to ship pre-installed on new phones from April 2014 ^[1]. New buyers would therefore meet the new software first, with existing users following as the update reached them.

Why it mattered

Cortana was announced as part of the operating system release, so the assistant, its developer API and the platform update arrived together ^[1][2]. Availability was staged by country, starting with a beta in the United States and moving on to the U.K. and China before wider release ^[1]. For Microsoft, the assistant was the most visible part of a phone update whose other pieces were practical additions — notifications, keyboard, speech; and the company's claim was that the assistant would keep getting better by learning about the individual user ^[1][2].