Tech giants Amazon (AMZN  ) and Microsoft (MSFT  ) are establishing a partnership to allow Alexa and Cortana, their respective voice-controlled digital assistants, to communicate with one another.

This means that users will be able to open Alexa through the Cortana's Microsoft 10 platform, or open Cortana through the Alexa interface. Data will not be shared between the two devices, however, so searches performed on one device will not appear on the other. The free communication capability is expected to go live later this year.

It is a somewhat unusual union for the two companies, which are typically fierce competitors in several areas. Amazon, for instance, has come to dominate the field of cloud computing through its Web Services Unit, drawing business away from traditional software building companies like Microsoft. Microsoft in turn has heavily invested in redesigning its own cloud network to be more competitive with what Amazon offers. The two companies have also competed over their employees, with each poaching workers from the other.

But there may be certain benefits to joining forces.

Smart assistants are a rapidly developing field, and Amazon and Microsoft are not the only two outfits vying to create the best product to win over the same pool of consumers. Google Assistant (GOOGL  ) and Apple's Siri (AAPL  ) are two such companies. There is a close rivalry between all four companies, but Google and Apple both have a unique advantage: devices.

Alexa and Cortana operate from homebound devices, while Google Assistant and Apple Siri can be used on smartphones. Apple and Google have a near duo-ply of the market, with their products accounting for 99% of all smartphone sales in the final quarter of 2016. Because consumers carry their mobile devices everywhere they go, they are more easily able to seamlessly adopt voice technology. A united Amazon and Microsoft may be better able to fight the hegemony of Apple and Google than either company could alone.

The benefits of the partnership are not limited to a competitive edge, however. Permitting versatile, multiple-platform access may make voice technology more convenient and useful to consumers who want to use their device with a number of companies that each offer their own unique strengths. Cortana, for instance, is integrated with Microsoft Office Suite, so that its users are able to access calendars, schedule meetings, and set reminders, while Alexa users can instantly place Amazon shopping orders. Limiting flexibility may only hamper the adoption of voice technology, which many still perceive as something of a novelty.

To that end, Amazon CEO Jeff Bezos has said that he is open to future collaborations with Apple or Google. And Microsoft, which has traditionally taken an aggressive tack with rivals, also seems to be more receptive to creating business partnerships under the leadership of CEO Satya Nadella. Microsoft now allows its software to run on devices created by Google or Apple, a significant shift from its former policy of restricting software to its own devices, and recently resolved a longstanding legal feud with Google.

Google and Apple may still have an interest in keeping their technologies separate, however, as they may feel that retaining their brand identity and strict control of user experience is more critical to their success than creating an open ecosystem for users.