A federal class-action lawsuit alleges that Duolingo, Inc. sacrificed lesson quality by swapping human contractors for artificial intelligence. The legal action focuses on a sharp drop in user growth. It aligns with what many educators and parents have suspected: the platform's heavy reliance on automated lesson creation has introduced errors that disrupt student focus.
What Happened
A securities class-action lawsuit filed in Pennsylvania claims Duolingo misrepresented its user growth while quietly replacing human curriculum designers with generative AI. According to the complaint filed by SueWallSt, the company's daily active user growth rate plummeted from 49% to 30% during 2025. This deceleration occurred after the app phased out human contractors in late April 2025. As we previously reported, the shift to automated tools has sparked widespread concern among educators. Parents and students began reporting frequent translation errors and unhelpful responses from the AI-powered Duolingo Max features.
The Bigger Picture
Research shows these quality issues are not unique to Duolingo. While the app launched 148 new AI-generated courses to expand access, experts note this rapid rollout came with a major trade-off in lesson depth. Educational researchers warn that AI tools often suffer from recognition errors and fabricated responses. A study on AI-assisted language learning published in PLOS One found that while AI can help with basic accuracy, it can lead to competence narrowing where students lose their ability to improvise conversationally. When platforms rely too heavily on automation, students can fall into a cycle of AI dependency instead of building independent skills. Educators agree that AI should only support language instruction, not replace human teachers.
What This Means for Families
For parents and teachers using the freemium app, the lower quality and increased monetization are clear. To offset AI operating costs, the platform has introduced heavier ads and aggressive upsells. Research on freemium subscription models shows that aggressive prompts can disrupt the habits that keep students engaged. The app's reliance on gamified mechanics, like loss-aversion streaks and badges, may keep kids logging in, but it does not guarantee they are learning high-quality language skills. When AI-generated errors slip through, students risk memorizing incorrect pronunciations or phrases.
What You Can Do
Parents can protect their child's progress by manually reviewing recent lessons for repetitive or incorrect translations.
To counteract competence narrowing, encourage your child to practice speaking with native speakers, teachers, or peers in real-world settings.
Finally, treat the app as a supplementary tool, not a tutor. Use it like digital flashcards rather than a comprehensive language instructor, and keep human oversight at the center of study.