Language learning app Duolingo is taking on music and math lessons

For tens of millions of users, language learning apps like Duolingo have provided an opportunity to freshen up on French or try their hand at Mandarin. The now 13-year-old language platform, which launched in 2011 with six languages (English, Spanish, French, German, Portuguese, and Italian), has since expanded to include 43 languages and added new skills for learners, which many users have probably avoided since high school.

Late last year, the company announced it would bring math and music lessons to the app. Users can learn musical concepts like pitch, meter, and rhythm and build the skills needed to shred “Mary Had a Little Lamb” on the app’s on-screen keyboard. Duolingo also teaches quotidian math skills like how to calculate tips and hourly wages.

The shift in learning offerings might seem like a peculiar move. In fact, Duolingo CTO and cofounder Severin Hacker said in an interview with Fortune Executive Exchange that the company considered everything from coding to history to geography when drumming up expansion ideas. Ultimately, its leadership chose to veer into math and music, believing they mesh well with the platform’s existing learning format.

“The way you learn languages on Duolingo lends itself well to those two subjects. You can learn them on the phone,” Hacker said. “You kind of pick it up on the go. We do have tutorials as well, but it's mostly learning by doing.”

A large part of this education model, used by almost 98 million people monthly, is bolstered by the company’s burgeoning A.I. use. The app has a new subscription tier that uses generative A.I. to role-play conversations, offer more thorough explanations to answers, and customize language lessons to best fit users’ needs.

“If you look at what is the best way to learn math, music, golfing, doesn't matter what, it is with a one-on-one tutor,” Hacker said, but he pointed out that personalized sessions are often expensive and inaccessible—issues that he thinks Duolingo can fix. “The promise of technology and A.I. is that you can reach that level of efficacy but actually make it accessible to everyone.”

Hacker added that there’s still much more room to leverage A.I. on the platform. “We're at 1% of what we could achieve with this company.”

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This story was originally featured on Fortune.com