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Duolingo is an app for Android that lets users learn languages quickly. Duolingo focuses on reading, writing, and speaking. The interface is made to feel like a game, and the app is completely free.
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Pros
Pro Frequently adding new languages
You can check out the courses page to see what languages are "hatching" (being developed) and what languages are in beta.
Pro Friendly, active community
There is a discussion board available on the site, and a really active community on reddit in r/duolingo (30k + members). Everyone is friendly and happy to help or offer support.
Pro Motivates through creative gamification
Progress is measured gaming-like by gaining XP, and leveling up. They use other creative gamification techniques to keep you motivated such as making wagers and improving your position on the leaderboard. Leaderboard compares your score to your friends' on the weekly, monthly and all-time level.
Pro Many languages
It's got a wide range of languages, some stable, some in beta and some still in the process of hatching.
Pro It checks your pronunciation
Speak to Duolingo to have it evaluate your pronunciation.
Cons
Con The hype in the community creates false ideas about what level Duolingo gets you to
Duolingo is a good tool for a beginner, and a good supplement to other resources. But it cannot get you from zero to understanding natives, tv, and books; and their "do the reverse tree and just speak" is usually not the correct answer to "what should I do after finishing the tree".
Con "Plays" like a Pay-2-Win-mobile-game
Has annoying in-app purchases.
Recommendations
Comments
Flagged Pros + Cons
Pro Generous free plan
Duolingo is completely free to use, with no features limited to upgraded accounts. If you want to go ad-free, the cost is $12.99/month.