Luis von Ahn was bored.
He'd created and sold two companies to Google. If you've ever typed a or reCAPTCHA on a website to prove you're human, von Ahn is the guy to thanks for that. But, sitting around in retirement wasn't going to cut it.
Since then, he's been channeling what he's learned about crowdsourcing knowledge into Duolingo, a free language learning platform that's teaching people foreign languages while little by little, translating the web.
"The goal is to make Duolingo the de facto way to learn a language around the world," he said.
Users sign up and pick a language to learn. Whether on a browser, mobile phone, or tablet, they work through a tree of skills, like adjectives, or possessive pronouns, with exercises that include speaking, listening, and translating.
A recent study by the City University of New York said that 34 hours spent on Duolingo equaled a semester of a language class. While Gina Gotthilf, head of marketing and international development at Duolingo says that Duolingo is not a substitute for the classroom, there are several reasons why Duolingo is proving effective.
For one, Duolingo is managing to keep users engaged. Online learning has a notoriously high dropout rate. About 40-50% of their more than 25 million users are active in the course, which might be due to how game-like the Duolingo format is.
While working through lessons, users have hearts, or lives, that they lose when they make mistake (inspired by the video game Zelda, a favorite of both Gotthilf and von Ahn). Users can also earn digital currency called lingots that can be used to buy extra lives, skills like flirting and idioms, or apparell for Duo the cartoon owl.
"We've been surprised by the number of people who claim to have started playing Duolingo while looking for a distraction, or game, and then unexpectedly became interested in learning a new language," von Ahn said.
Gotthilf also said they A/B test everything on Duolingo to find out what keeps people coming back. They test for which order to put skills in on the tree, down to how many tears Duo cries if a user fails a skill (one with a sizable puddle, for now).
On the web version, users also have the option to practice their translation skills with real articles from sites like CNN and Buzzfeed.
"A lot of people do because it gives them a chance to test out how they're doing in terms of a real world scenario," Gotthilf said.
The translations are also a key component of how Duolingo makes its money. The app is free, so Duolingo keeps the lights on by selling the translations that users do. Users essentially check each other and vote on the best translation as new language speakers are bound to make mistakes.
Translating language learning
Though Duolingo considers itself more a game than a MOOC, they're still dealing with the challenge of how to bring language learning online.
"We believe that in order to most effectively bring education online, you can't just take what's offline and throw it online," Gotthilf said. Merely posting a lecture online ignores the many other factors attached to being in a class, like being in the same room as the professor, and being surrounded by peers.
On the flip side, Gotthilf said that something like Duolingo can outperform a classroom experience through things like adaptive questions within the lessons and tests, even focusing on words with which the user is struggling. So instead of a professor having to teach to the middle of the class- not being too challenging or too basic- the individual student can progress at a rate specific to them.
"We now have the advantage of being able to to improve education at a rate that wasn't possible before by analyzing the data of millions of students at a time, to personalize learning in a scalable manner, and to engage students in completely novel ways," von Ahn said.
Going forward, Duolingo is looking at launching Pen Pals, a way for user to practice their speaking skills with others, supported by prompt (think how Google suggests the rest of your searches) that will keep conversation moving beyond awkward introductions.
At baseline though, Gotthilf said the goal remains to make the highest possible quality of language learning available to all.
Erin Carson has nothing to disclose. She doesn't hold investments in the technology companies she covers.
Erin Carson is a Staff Reporter for CNET and a former Multimedia Editor for TechRepublic.