In just a few short years, Apple's Siri, Amazon Alexa and Google Assistant have gone from being virtual unknowns to familiar household names. And as these voice assistants and others continue to gain traction on smartphones and smart speakers, the market is expanding quickly. So much so that eMarketer, in a new report, proclaims that voice-control technology “has officially moved out of the early-adopter phase and into the mainstream.”

According to the latest eMarketer data, an estimated 111.8 million people in the U.S. will use a voice assistant at least monthly this year, up 9.5% from 102.0 million 2018. This amounts to 39.4% of U.S. internet users and 33.8% of the overall population. By 2021, the number of U.S. voice assistant users will reach 122.7 million, representing 42.2% of U.S. internet users and 36.6% of the U.S. population.

For radio broadcasters, the mainstream adoption of voice assistants means more consumers are getting comfortable using voice commands to access their favorite radio stations and shows – on their smart speaker, smartphone, and soon, in the car. But consumers are saying “Hey” to Siri, Google and Alexa for more than just audio entertainment. Top tasks also include getting directions, making phone calls, and finding nearby stores, according to a Social Lens Research study conducted in August 2018.

Voice assistant use also cuts across various demographics, eMarketer finds. For example, there will be 57.6 million female and 54.2 million male voice assistant users in the U.S. this year. This equates to 34.4% of women and 33.3% of men who use voice assistants at least monthly. “While early use tended to skew slightly more female, the percentage of males using voice assistants has accelerated in recent years,” eMarketer says in the new study.

Currently, most people use their voice assistants on smartphones and smart speakers with the latter most common by a wide margin. That’s not surprising, given the sheer numbers: The U.S. penetration rate for smartphones is 70.5%, and most models now come equipped with—or can download—voice assistant software.

Smart speaker use is also on the rise. The eMarketer forecast is for 77.6 million users in the U.S. this year, representing 27.3% of U.S. internet users and 23.5% of the population. By 2021, this figure will grow to 88.7 million users, or 30.5% of U.S. internet users and 26.5% of the population.

“Over time, we expect the number of voice-assistant users to rise even further as the software finds its way into more devices, including cars, wearables, smart TVs, appliances and other connected gadgets,” the report offers.