Luis Von ahn on A/B testing
From The Inventor of CAPTCHA’s Secret Language Hack | Learn Chinese 語言 [yǔ yán] | Luis von Ahn · · ShaoLan: Chineasy & Lifeasy
“If we want to teach plurals before adjectives or adjectives before plurals, what we do is we just do a test for the next 50,000 people that sign up and then it takes about 6 hours to get 50,000 new users on Duolingo. So for the next 50,000 people that sign up, to half of them we teach them plurals before adjectives and to the other half at random we teach them adjectives before plurals. And then we measure which ones learn better and which ones stay for longer.”
On , Luis Von ahn, CEO & Co-Founder at Duolingo, spoke about A/B testing during The Inventor of CAPTCHA’s Secret Language Hack | Learn Chinese 語言 [yǔ yán] | Luis von Ahn on ShaoLan: Chineasy & Lifeasy.
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About Luis Von ahn
In recent interviews and earnings calls, Luis von Ahn stated that Duolingo has never conducted layoffs, despite what he described as rumors on the internet. He argued that AI makes individual employees more productive, which he said increases the return on investment from hiring. Von Ahn was quoted as saying, "AI is not going to take your job. Somebody using AI is going to take your job." He described an internal "golden rule" that Duolingo only uses AI to benefit learners, and noted that two employees without engineering backgrounds used AI to build a chess course in six months that became the company's fastest-growing course. Von Ahn discussed a strategic shift in 2026 toward prioritizing user growth over revenue growth, which he acknowledged led to lower revenue estimates and a negative reaction from the stock market. He said the company's daily active users grew 21% year-over-year in Q1 2026. Von Ahn also commented on the company's mascot, revealing that he personally wrote a notification message that reads, "These reminders don't seem to be working, so we'll stop sending them," which he said he did not intend to be manipulative. He added that Duolingo had a video concept where the owl would "try to kidnap people" but decided not to release it.