Duolingo rolled out its most extensive content update ever on April 30, 2025, adding 148 new language courses developed with generative artificial intelligence. This expansion, which the company stated more than doubles its course offerings and makes popular languages like Japanese, Korean, and Mandarin available across all 28 of its supported interface languages, arrived under a cloud.
Just one day prior, the company confirmed an internal “AI-first” mandate that includes phasing out human contractors for tasks AI can perform.
AI Powers Course Creation at Scale
The language learning company credits AI for the rapid development cycle. “Developing our first 100 courses took about 12 years, and now, in about a year, we’re able to create and launch nearly 150 new courses,” CEO Luis von Ahn stated in the launch announcement, calling it “a great example of how generative AI can directly benefit our learners.”
Duolingo used a “shared content” system, leveraging AI for generating and validating materials that could be quickly adapted across languages. This expansion specifically benefits learners globally; for instance, Spanish and Portuguese speakers in Latin America and speakers of fifteen European languages gain access to courses for Japanese, Korean, and Mandarin, while users in many Asian countries can now learn Duolingo’s top seven languages beyond just English.
Duolingo asserts human expertise remains involved despite the AI acceleration. Jessie Becker, Senior Director of Learning Design, stated, “Now, by using generative AI to create and validate content, we’re able to focus our expertise where it’s most impactful, ensuring every course meets Duolingo’s rigorous quality standards.”
The company has previously said that even for AI features like Roleplay, humans write the initial scenarios and prompts and review AI outputs. However, the speed and scale achieved raise questions about the depth of human review possible for 148 courses built in under a year.
Shift to an “AI-First” Operation
The technological feat of the course expansion is intertwined with a strategic pivot announced internally on April 29. Duolingo is shifting to be “AI-first,” a move von Ahn compared to the company going “mobile-first” in 2012.
This new direction designates AI as the “default starting point” for work, requires staff (“Duos”) to spend 10% of their time learning AI tools, and suggests coding might become less central. A key component involves reducing reliance on contractors. Von Ahn reportedly explained in the internal memo that manual content creation doesn’t scale for the massive amount needed to teach well.
He also stated that new hires would only be approved if automation wasn’t feasible, introducing what sources called “constructive constraints” tying AI use to performance and headcount. While aiming to reassure staff (“This isn’t about replacing Duos with AI. It’s about removing bottlenecks so we can do more with the outstanding Duos we already have,” von Ahn reportedly wrote), the move follows earlier workforce adjustments.
Backlash and Lingering Questions
In January 2024, Duolingo cut about 10% of its contractors, with a spokesperson later confirming to media outlets that “AI is contributing to the reduction,” though not the sole cause.
Von Ahn had previously signaled this direction in 2024, stating the company’s stance iss “if we can automate something, we will,” and mentioning AI’s role in content scaling in shareholder communications as early as November 2023.
Despite Duolingo framing the AI push as beneficial for learners by expanding access, the strategy’s confirmation and the contractor news provoked immediate backlash online. Users took to social media platforms like X (formerly Twitter) and LinkedIn to voice concerns.
Some reported perceived drops in content quality and accuracy, particularly in less common language courses, attributing it to increased AI use. Others expressed disappointment at the company seemingly prioritizing automation over the human element often associated with language learning, leading some to delete the app and call for others to do the same.
Duolingo’s use of AI isn’t entirely new; it has used its “Birdbrain” AI for personalized exercise difficulty for some time and launched its premium “Duolingo Max” tier in March 2023 using OpenAI’s GPT-4 or features like “Explain My Answer” and conversational “Roleplay.”
The new courses themselves focus on beginner levels, roughly corresponding to A1-A2 on the Common European Framework of Reference for Languages (CEFR), a standard scale of language proficiency. They include reading (Stories) and listening (DuoRadio) features, with more advanced content promised later.
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