Duolingo slapped with class-action lawsuit alleging AI efforts, relentless ads hurt user growth
Popular language-learning app Duolingo is facing a class-action lawsuit accusing its executives of keeping investors in the dark about monetization and AI efforts that drove away customers. Investors who acquired Duolingo shares between May 2, 2025, and Feb.26, 2026, are eligible to file as claimants in the securities fraud lawsuit, which was filed earlier this month by Levi & Korsinsky, LLP, in US District Court for the Western District of Pennsylvania. The suit alleges Duolingo executives relentlessly advertised paid subscription tiers to users on the free version of the app and implemented low-quality AI features that they knew would frustrate customers, even as they told investors they were prioritizing user growth. “With increasing frequency, the Company forced free users to watch unskippable ads after each lesson, plus additional monetization for [paid tiers] Super and Max, creating scenarios where free users were spending as much or more time on watching ads than lessons,” the suit said. “The Company’s ad push was so aggressive that it saw users snap years-long participation streaks just to avoid being bombarded with the Company’s aggressive ad campaigns and monetization push.” The lawsuit also alleged that unbeknownst to investors, in another effort to boost monetization, Duolingo rolled out a new feature called Energy to replace its old Hearts system.With the old Hearts system, free users lost one heart for every wrong answer, and when their hearts ran out on a given day, they had to wait for them to replenish before completing a new lesson.
It allowed customers to use Duolingo — known for its green owl mascot — for extended periods of time without paying.The Energy system, however, causes users to lose energy with every correct and incorrect answer – meaning even if they complete a flawless lesson, they are still using energy.Some energy can be replenished by watching even more ads, but for full energy, customers need to wait u...