Last May Duolingo's stock peaked at $529.05. But while the learning app passed $1 billion in revenue in 2025 and 50 million daily active users, today its stock price has dropped more than 81%, to $100.51. And there's been other changes, reports Entrepreneur:In April 2025, Duolingo CEO Luis von Ahn made headlines after writing a memo calling the company "AI-first." In the memo, von Ahn announced that the language-learning platform would track employees' AI use in performance reviews. Now, a year later, von Ahn is backtracking and rethinking how he measures employee performance. He told the Silicon Valley Girl podcast earlier this month that Duolingo no longer considers AI use in performance reviews. The change arose after employees started to ask, "Do you just want us to use AI for AI's sake?" von Ahn explained. "We said no, look — the most important thing in your performance is that you are doing whatever your job is as well as possible. A lot of times, AI can help you with that, but if it can't, I'm not going to force you to do that," von Ahn said on the podcast. He felt as though the company was "trying to push something that in some cases did not fit" instead of "being held accountable for the actual outcome." The CEO is, however, still sticking to other "constructive constraints" he introduced in the April 2025 memo, including stopping contractor hiring in cases where AI can assume their workload... Von Ahn also mentioned that a few months ago, Duolingo had a day dedicated to vibe coding, or prompting AI to create an app without manually writing a single line of code. Every single person at the company, from engineers to human resources professionals, had to vibe code an app. Vibe coding has made an impact at the company. One of Duolingo's latest offerings, a course teaching users how to play chess, arose when two people vibe-coded the first prototype of it, the CEO said. Neither of them knew how to play chess or program, but they managed to use AI to create the whole chess curriculum and a prototype of the app in about six months last year. Now chess is Duolingo's fastest-growing course, according to von Ahn. "At this point, we have seven million daily active users that are learning chess," the CEO said on the podcast.Read more of this story at Slashdot.