Can AI Replace Human Teachers? Inside Duolingo’s Controversial Language Learning Revolution

Can a AI chat bot replace a person when learning language? Duolingo fully relies on artificial intelligence, releases translators and harvests shitstorms. The number of users and language courses still rise rapidly. The violent criticism seems to fizzle out.

The Duolingo language learning app exceeds the Wall Street forecasts and highlights its annual prognosis because more and more users pay for AI-based functions. However, the financial success is overshadowed by controversy about the personnel strategy. The company recently introduced 148 new language courses that were created with generative AI – the largest content extension in Duolingo’s history.

From twelve years to twelve months

The figures illustrate the speed of AI-based development: While the first 100 courses needed about twelve years of development, the new 148 courses were completed in just one year. This increase in efficiency made it possible to almost double the course offer and to offer languages ​​such as Haussa, Navajo or Xhosa, which were previously not economically presented due to the high development effort.

The company uses a combination of large voice models such as Openais GPT-4 and its own machine learning software. The AI ​​not only creates exercises and dialogues, but can also take complex grammatical structures and cultural nuances into account. However, this technology is based on non-exclusive voice models, which has long-term competitive risks.

Criticism of the “Ai-First” strategy

In one now public email CEO Luis von Ahn announced the changeover to an “AI-First” strategy. His statements were particularly critical that Duolingo would “stop gradually to use contractors for work that AI can take over” and that “AI use would become part of the performance assessment”.

According to journalist Brian Merchant (via Polygon) If this is not a new development: Duolingo had already released about ten percent of his contractors at the end of 2023, followed by further cuts in October 2024. In both cases, translators and later authors were first replaced by AI. This development led to violent reactions on social media, where users deleted their long -term learning streams and switched to competition.

Financial successes despite controversy

The numbers, on the other hand, speak for the AI ​​strategy: in the first quarter of 2025, the number of daily active users rose by 49 percent to 46.6 million. The paid subscriptions recorded an increase of 40 percent to over ten million. For the second quarter, Duolingo expects sales between 238.5 and $ 241.5 million (around 209 to 212 million euros). The forecast annual turnover For 2025 is between $ 987 and $ 996 million (around 866 to 874 million euros)-well above the analyst estimates of $ 977.2 million (around 858 million euros).

Especially the premium functions such as “Duolingo Max” with AI-supported tutor and role-playing features drive growth. So far, the controversy around the personnel strategy does not seem to have a negative impact on the number of users. Duolingo benefits from a general trend towards digital language learning and the increasing acceptance of AI-based education tools. Nevertheless, it remains to be seen whether the long-term quality of the AI-generated content can keep up with human-created courses.