Alexa, open Cortana! Microsoft Corporation (MSFT) and, Inc. (AMZN) have teamed up their respective voice assistants in a bid to improve usability and combine the "unique strengths" of each assistant. 

In an interview with The New York Times, Amazon CEO Jeff Bezos articulated a future in which numerous forms of artificial intelligence will be integrated into a single device. He likened the integrations to having access to multiple friends, with each friend offering recommendations based on his or her expertise. Microsoft CEO Satya Nadella made a similar comparison by drawing parallels between competing browsers and voice assistants. According to Nadella, the personality and expertise of each assistant will benefit users because "they will get more out of it." (See also: Amazon's Alexa, Microsoft's Cortana Gain Ground on Apple's Siri.)

The move will dramatically expand the market for the voice assistants of both companies. Amazon's Echo dot series, which uses Alexa, is the market's most popular smart speaker. An integration with Cortana will enable a greater number of use cases for the device. For example, Alexa users will be able check up on their calendar appointments in Microsoft Outlook. While Amazon's device has its own scheduling and productivity features, Microsoft's Office suite of products is the best-selling productivity solution on the market. At the same time, the partnership will allow Microsoft users to conduct their e-commerce transactions using Cortana and access Alexa's diverse array of skills. (See also: Microsoft Is Adding Cortana to Its Office Suite.)

The market for smart speakers is expected to reach $13 billion by 2024. That figure encapsulates sales of over 100 million units. Several technology behemoths have joined the race to develop smart assistants that will enable them to bring an increased array of services to customers. For example, Samsung Electronics Co. Ltd. (SSNLF) already has its Bixby voice assistant and will unveil its own smart speaker later this year. Apple Inc. (AAPL) and Alphabet Inc. (GOOG) subsidiary Google have also released smart speakers of their own. In his NYT interview, Bezos said that he would welcome a smart speaker integration with both of those companies, but Apple and Google declined to comment for the article. (See also: Sears Skyrockets on Amazon Alexa Deal.)