The two companies first announced the collaborative deal a year ago, in which their respective virtual assistants would be able to work together. Starting with the US, initial integration between Cortana and Alexa devices is now open to the public.
"This integration will allow Cortana users to ask Alexa to shop on Amazon, manage their Amazon orders and access many of Alexa's third-party skills. Alexa users will have access to Cortana's knowledge and helpful productivity features such as calendar management, day at a glance and rich email integration. Over time, additional skills and features will be integrated," a Microsoft spokesperson said.
In this "public preview" release, users can now talk to Cortana via their Echo devices and to Alexa on Windows 10 devices or the Harman Kardon Invoke speakers, powered by Cortana. As the collaboration deepens, it is anticipated that more skills will become available, enabling a wider range of commands and tasks to be shared. Streaming music across different digital assistants, for example, is a skill not yet available. More device types and skills will be available in due course, the Microsoft spokesperson said.
Microsoft and Amazon officials say the goal of their integration agreement is to have Cortana and Alexa able to carry out a required task wherever and on whichever device is most convenient to the customer. Cortana and Alexa can each be enabled as a skill on the other.
On a Windows device, users need to say "Hey Cortana, open Alexa". On an Alexa-powered Echo, users need to say "Alexa, open Cortana." It is not (yet) possible simply to speak to a Windows device as if it were an Amazon device.
User data from each company's device will not be shared with the other, a fact both Microsoft and Amazon have been keen to stress. The data collected by the virtual assistants will be controlled by their respective companies, in line with existing privacy policies.
"No raw data will be shared between companies," Microsoft said. "Once you open Cortana, all voice data goes to Microsoft not Amazon, and once you open Alexa, all voice data goes to Amazon and not Microsoft."
Up to now, Microsoft's Cortana has languished some way behind Alexa, Google Assistant and Apple's Siri in terms of end-user adoption, although its inclusion in Windows 10 has allowed it to gain a foothold in offices.
For its part, Amazon is bringing Alexa to new Windows 10 PC models with a dedicated app that listens for any "Alexa" voice commands, bypassing Cortana entirely. Whether this move bolsters or scuppers this cross-platform assistant collaboration is open to question.
Amazon CEO Jeff Bezos told the New York Times that he envisions a future world where our devices will automatically forward voice commands to whichever virtual assistant is best suited for the task. "In my view of the world, because that would be best for the customer, that's probably what eventually happens," he said.
Voice technology and virtual assistant AIs were the clear focus of CES 2018, with Google plastering its Assistant all over the city of Las Vegas.