While the little green owl always had ambitions to grow up to be a great foreign language teacher, the initial focus was on a crowdsourced revenue model that was entertaining and free. With 50 million users around the world, the Pittsburgh-based company is now moving away from the crowdsourced translated text that it sells to paying customers like CNN and BuzzFeed, although this will continue on a smaller scale. Increasingly, the the emphasis is on an adaptive platform that tailors teaching to the strength and weaknesses of individual learners.

Luis von Ahn

“With technology, we now have a means to do this in a scalable way never possible before,” says Luis von Ahn, CEO. Ahn, 35, grew up a privileged child in Guatemala and is sympathetic to the barriers faced by the poor in developing countries. Duolingo’s global students want the best possible language education. “We think of it as a one-on-one tutor. It will test you and generate a personal lesson plan just for you,” he says.

Von Ahn compares the level-by-level curriculum to a tree. A beginner starts out at the roots, learning basics like simple sentence structure and vocabulary, and moves up and out vertically through the branches to take on more challenging lessons in vocabulary, grammar, comprehension, translation, and pronunciation. “The tree effectively rearranges itself to suit individual learning styles,” he says.

Duolingo software engineer Matt Streeter elucidates further on the structure: “Instead of being presented with a fixed ‘tree’ of skills to learn when you first sign up, your tree will evolve as you progress through the course,” he says. “Within each lesson, the sequence of questions will adapt depending on your previous answers, and will be personalized based on what you’ve told us you want to accomplish as well as what we’ve inferred about you from previous lessons you’ve done.”

Severin Hacker and Luis von Ahn, cofounders of Duolingo



The new platform is being tested beginning this month. The first change Duolingo users will notice is the heart reward system is gone, replaced by a strength bar that rises and falls based on how well each concept is mastered. Success is measured not only by how many questions the user gets right or wrong, but how well the game is played. Feedback so far indicates that Duolingo users don’t miss the hearts at all.

“I’ve actually been really enjoying this change,” wrote one user on a Duolingo subreddit. “I felt the hearts system could too easily become a source of frustration.”