But Duolingo’s success will depend in no small part on whether the site can keep users coming back. To that end, the system has been tested and updated continually since the fall of 2010.
“A huge part [of making it successful] is that you just need to experiment. It’s nothing but trial and error,” says Severin Hacker, a PhD student at Carnegie Mellon and the lead architect of Duolingo.
Initially, Duolingo will launch with just three languages: English, Spanish, and German. The eight-member team working on the project had originally intended to tackle more, but they soon discovered that development time was too slow for languages that were not native to at least one team member.
Severin says the multilingual nature of Duolingo was one of the biggest challenges in its development. Users with keyboard layouts intended for English, for example, cannot easily generate special characters used in other languages, such as the umlaut in German. As a result, developers and the team’s designer had to put a lot of effort into honing the interface, including developing a fast and intuitive virtual keyboard for generating these characters.
Aside from the promise of free language instruction, it isn’t clear how Duolingo may entice users. But many of von Ahn’s past projects have involved casual games designed to encourage them to perform useful tasks that computers can’t manage on their own. (One game he developed, which makes it fun for users to label images, was later purchased by Google and now enhances the utility of Google Image Search.)
“A hard thing when learning a language is just staying motivated,” says von Ahn. “A large fraction of people want to learn a language, but at end of day it is hard to do it. We had to tackle that problem.”
Another hurdle to the success of Duolingo is that unlike recaptcha, which is embedded on countless websites, Duolingo will require that users show up in the first place. Von Ahn says he has no idea whether it will generate sufficient attention, but interest is already high. So many people have already signed up for the private beta, he says, that “if we only had those users, we could already translate a lot of stuff.”