“Artificial intelligence has always been a huge part of our strategy,” says principal product manager Edwin Bodge. “We had been using it for personalizing lessons and running Duolingo English Tests. But there were gaps in a learner’s journey that we wanted to fill: conversation practice, and contextual feedback on mistakes.”

Duolingo turned to OpenAI’s GPT‑4 to advance the product with two new features: Role Play, an AI conversation partner, and Explain my Answer, which breaks down the rules when you make a mistake, in a new subscription tier called Duolingo Max.

“We wanted AI-powered features that were deeply integrated into the app and leveraged the gamified aspect of Duolingo that our learners love,” says Bodge.

Duolingo engineers had tried using GPT‑3 to supplement some of the human-powered features in its earlier chat feature. “It was close to being ready,” said lead engineer Bill Peterson, “but we didn’t feel it was at the point where we could confidently integrate it to handle the complex automated aspects of chats.”