Duolingo, the popular language-learning service founded by CAPTCHA co-inventor and reCAPTCHA founder Luis von Ahn, just launched the latest version of its mobile app for the iPhone. This new version introduces an offline mode, so users can now do their lessons on the subway and on planes, as well as a voice-recognition feature that tells learners whether they pronounced a word or sentence correctly.
As von Ahn told me earlier this week, offline access has always been one of the most requested features for Duolingo . The app now caches about an hour’s worth of lessons and then syncs with Duolingo’s servers once it is back online. Interestingly, this also means that the app is now always a bit faster, because even when users are online, most of the lessons now don’t have to be downloaded on demand.
The only feature that doesn’t work offline, however, is the new speech-recognition tool because the actual speech recognition is handled by Duolingo’s servers. This new feature, von Ahn told me, checks how close your pronunciation is to a native speaker and then provides some basic feedback.
Duolingo previously offered this feature on its website (and they both use the same backend), but as von Ahn told me, about half of the lessons on the service are now completed on the iPhone. On average, users now spend more time with the mobile app than on the website.
Looking ahead, Duolingo plans to launch an Android app with all the functionality of the iOS app in May.
In addition, the team is working on reimagining the translation experience. As you may recall, the original idea behind Duolingo was twofold and similar to von Ahn’s last startup, reCAPTCHA: Duolingo would teach users how to speak and write a language, and, in return, users would translate online texts into other languages once they got proficient enough to do so (and Duolingo would be able to charge for these translations). Right now, however, von Ahn told me, “users like the lessons more than the translations – and I don’t want that.” So the Duolingo team, which consists of about 26 people, is working on redesigning the translation part of Duolingo, though it’s not clear when the team plans to launch this.