Luis von Ahn | Crain's Pittsburgh

In this ongoing series, we ask executives, entrepreneurs and business leaders about mistakes that have shaped their business philosophy.

Luis von Ahn


Duolingo is a free, science-based, language-learning app that offers 53 language courses for 23 different languages and has 120 million users around the world.

The Mistake:

We took a really long time to officially launch Duolingo in India because we were under a major misconception. We’d launched language courses all over the world and had so far been able to let them grow organically without paying much attention.

However, unlike most countries, Duolingo in India was not a hit. We had very few users and, moreover, it seemed like our few Indian users were learning French and Spanish rather than English, which is normally the most-coveted language in non-English speaking countries.

We asked around and were told by an Indian native in the tech field that people who owned smartphones in India were probably affluent and therefore likely to have some knowledge of English. This made sense at the time, and we had many priorities and put the issue to the side.

Finally, one of our investors, Google, said to us, "India is a huge and growing country. Go over to India and figure this out." So five of us went in February [of 2016]. When we arrived, we began talking to people and realized right away that the original assumption was incorrect: Most people barely spoke English and were interested in learning it.

We’d also assumed, worldwide, that people’s phones were set to a language they were fluent in. Therefore, people whose phones are in English are offered courses made for English speakers on Duolingo such as French and Spanish, but not a course to learn English.

In India, however, most people’s phones are set to English because typing in Hindi is very difficult. Therefore, most people with smartphones did want to learn English but couldn’t access our English course at all. They were downloading our app, looking for English and that option was nowhere to be found.

Check all your assumptions.

The Lesson:

Once we realized this, we solved the problem right away. The key lesson we learned is to check all your assumptions. As soon as we made these changes, our business in India started to grow.

It may seem like a very small matter, but it was an important lesson that we will apply to other countries. If we hadn’t gone to India, we would have never known. We’ve spent two years ignoring India, a country with 300 million people who want to learn English. Now that we’ve gone to India and figured this out, our traffic will probably double.

As a result, we’re now starting to look at other countries and check our assumptions there.

Follow Luis von Ahn on Twitter at @luisvonahn and Duolingo at @duolingo.

Photo courtesy of Luis von Ahn

Do you have a good story you'd like to share, or know someone we should feature? Email

And be sure to sign up for our newsletter at Crain's.