Users in China found the Pittsburg-based app unavailable for downloads last August amid the country’s sweeping education crackdown, including restrictions on for-profit afterschool tutoring. At the time, Duolingo told local media that the company “received instructions to strengthen the app’s content compliance mechanism.” The app entered China in 2019.

China has in recent years been closing regulatory loopholes in apps of all kinds. Data-heavy services from video games to livestreaming platforms are asked to implement strict content moderation in order to sustain a “healthy” digital environment.

While the core services of American titans like Twitter, Facebook, Instagram and Google have long been unavailable in China, a handful of other foreign tech companies began to voluntarily shutter or revamp their products in the country as Beijing introduced new strict data laws that led to rising compliance costs.

Yahoo, TechCrunch’s parent company, pulled its services from China altogether last November. LinkedIn rolled out a Chinese version of its professional networking platform with limited features. Nike this week said it would replace its running app with a localized solution for China.

Those who still see China as a potentially lucrative market will likely stay but work to meet the country’s changing internet policies. And oftentimes that means the global version of their apps or services won’t be compatible with China’s new regulatory environment.

Duolingo is among those that continue to operate in China by tailoring their service to the country. The reintroduced app, according to its official social media post this week, is free to use, teaches 41 languages and comes with gaming features. The most notable update is that it will start teaching Cantonese, the language spoken by people in Hong Kong and Macau, as well as a significant population of the affluent Chinese province of Guangdong and the Chinese diaspora around the world.