Duolingo, one of the hottest learning startups around is launching in Hindi. On the new iOS version of the app, users will be able to learn English in Hindi. You can also learn a set of languages such as Spanish, French, Italian and German on the app.

The popular free language learning startup, launched by Luis Von Ahn, the inventor of reCaptcha and Carnegie alum Severin Hacker, has 28 million users worldwide. The app has been downloaded over 17 million times on iOS and 15 million times on Android.

The app will always be free to its users, the company said.

The startup had raised $20 mn Series C funding from Kleiner Perkins Caufield & Byers. It had earlier raised $15 mn in Series B funding from NEA in 2012 and Series A from Union Square Ventures in 2011. Actor Ashton Kutcher and author Tim Ferriss are also investors in the company.

Instead of charging users for the app, the company makes money by getting users to translate texts (like how they used reCaptcha to crowdsource digitization of printed books) which is sold to media companies like CNN and BuzzFeed.