Amazon.com's Echo and Echo Dot devices will claim a 70.6 percent share of the U.S. market this year, according to a study relased by eMarketer.
The speakers feature Alexa, Amazon's voice-controlled aide, which users can tell to play music, order an Uber or turn on the house lights.
That puts it far ahead of Alphabet's Google Home, a similar gadget that has a 23.8 percent share, and less successful offerings from other tech companies.
The number of active U.S. users will more than double for the devices this year, to 35.6 million, eMarketer said.
Amazon has made progress in making Alexa and its speech-recognition technology an integral part of customers' lives. More users means more data that can improve Alexa's understanding and could make it a top platform for voice, like Windows is for desktop.
The statistics from eMarketer focused on speakers and left out other virtual assistants, such as Apple's Siri and Microsoft's Cortana. More than 60 million in the United States will use virtual assistants at least once monthly in 2017, eMarketer's report said. That's over a quarter of U.S. smartphone users.