The lawsuit, City of Dearborn Heights Act 345 Police & Fire Retirement System v. Duolingo, Inc., claims that the language learning firm deliberately compromised its user experience to force monetization. According to the complaint, Duolingo allegedly increased ad volume and pushed subscription tiers while relying on AI-generated content that degraded overall product quality. Plaintiffs assert that internal A/B testing revealed these tactics were actively eroding user retention and Daily Active User (DAU) growth, facts which were purportedly withheld from the investing public.

Kahn Swick & Foti, LLC, the firm representing the class, alleges that these actions undermined the company's financial sustainability despite claims of product improvement. Investors affected by the stock performance during this window are encouraged to contact managing partner Lewis Kahn. While the court deadline for seeking lead plaintiff status is December 7, 2026, those who suffered losses during the period may still be eligible to participate in potential recoveries without serving as a lead plaintiff.