Duolingo releases a new app version weekly, with roughly 350 changes per version, according to von Ahn. Von Ahn emphasized that the offering remains in early testing and represents only a small share of subscribers. Von Ahn said the cost has since fallen below $0.01 per call, largely through the use of open-source models. Von Ahn said China monetizes at roughly the same level as France and could become Duolingo’s largest market by DAUs within one or two years. Founded in 2011 by Luis von Ahn and Severin Hacker, Duolingo offers a freemium service featuring bite-sized lessons, gamified exercises and adaptive learning algorithms.