History-making companies begin with a vision. For Luis von Ahn, Duolingo was synonymous with the vision to deliver language education to everyone. Having grown up in Guatemala, Luis came to realize that learning English was a privilege, one that at least doubles a person’s income potential. It was his mother who taught him English from a very young age.

After immigrating to the U.S. at the age of 18 to study math at Duke University, Luis went on to become a computer science professor specializing in human-based computation. It was there that he posed a question to his top Ph.D. student, Severin Hacker, “How can we get 100 million people translating the web to every language for free?” The inspiration behind the question was Luis’ ambition to create a language learning platform that people could use to gain the economic advantages that often come with being at least partially bilingual.

Providing equal access to education for everyone is a lofty goal, and one that some EdTech companies were already tackling with a traditional educational approach. Luis and Severin had a different path in mind—delivering a highly engaging experience for language learners through gamification.

It was that gaming element that caught the attention of Kleiner Perkins partner Bing Gordon when he was approached by USV’s Brad Burnham about Duolingo in 2013. Having spent a decade as the chief creative officer at Electronic Arts, Bing knows games, and was pleasantly surprised by Duolingo’s product design and team.

Though the company didn’t have a path to monetization at the time, it was clear that Luis and Severin were building something special in Pittsburgh, PA. The city has become an intrinsic part of Duolingo’s journey, as has A/B testing. If you speak with anyone on the Duolingo product team about how their app has become so popular with users, you will hear about data and constant measurement. Every part of the app—from first-time user experience and session flow, to challenge management and learning efficacy—is A/B tested with rigor. When Bob came on board as the chief revenue officer in 2016, he took the A/B testing and experimentation that was working so well for user growth, and applied it to monetization.

Chief Product Officer, Jorge Mazal (also a KP Fellows alum) says it best, “The people are what make Duolingo special.” Employee retention is incredibly high at Duolingo, as is their obsession with users. That longevity, and Duolingo’s highly collaborative culture of learning, are the makings of an enduring company. The “Duolingo approach” of doing a good job at teaching a subject in a fun and highly-personalized way leaves the door open for many possibilities, and it’s clear the team plans to expand into other areas of education.

From all of us at Kleiner Perkins to Luis, Severin, Bob, Jorge, Natalie and all those who have been part of building Duolingo: Congratulations. We’re very fortunate to be part of your journey, and we know that this is just the beginning.