In an unusual partnership, Amazon and Microsoft are working together to extend the abilities of their voice-controlled digital assistants.

SEATTLE — The crowded pack of voice-controlled digital assistants — Apple’s Siri, Google Assistant, Amazon’s Alexa and Microsoft’s Cortana — are good at numerous things. They can help people play music, set up calendar appointments and check the weather.

They can even get two rival tech executives, Jeff Bezos of Amazon and Satya Nadella of Microsoft, to join hands in a rare partnership.

For the past year, the two companies have been coordinating behind the scenes to make Alexa and Cortana communicate with each other. The partnership, which the companies plan to announce early Wednesday, will allow people to summon Cortana using Alexa, and vice versa, by the end of the year.

It is unusual for big tech companies to cooperate on important new technologies that they want to stand out from the competition. Amazon, Apple, Microsoft, Google and nearly every other big tech company is pouring huge amounts of money into making digital assistants that are smarter and can do more, seeing them as a new way for people to interact naturally with devices and online services.

But Mr. Bezos and Mr. Nadella are concerned that keeping assistants from working together could hold them back. The way they see it, each assistant has unique strengths that could benefit the other assistants.

In an interview last Friday at one of Amazon’s Seattle high-rises, Mr. Bezos predicted that over time people would turn to different digital assistants — also called “A.I.s,” for artificial intelligence — the same way they turn to one friend for advice about hiking and another for restaurant recommendations.

“I want them to have access to as many of those A.I.s as possible.” Mr. Bezos said.

As an example, Mr. Bezos cited Cortana’s superior integration with Outlook, the popular calendar and email application that is part of the Microsoft Office suite of software. Because Microsoft controls both products, Outlook is integrated more deeply with Cortana than with other voice assistants. Through its collaboration with Microsoft, Amazon said, Alexa users will get answers to some of the same questions that Cortana can now answer — for instance, when is the next budget review with the boss?

 

Source: ‘Cortana, Open Alexa,’ Amazon Says. And Microsoft Agrees.