Duolingo

Duolingo is a game-based language learning tool. Beginners first choose a language from a list of over three dozen options and then start with the Basics lessons. More advanced learners can take a quick placement test to determine the appropriate starting point. Instructional practice activities cover all four skills (reading, writing, speaking, and listening) and require students to go back and forth between the target language and their self-identified native language. When students make an error, they see the correct answer. Students can also practice conversational, situational language skills in the Stories section. Students see their streak count (their number of days in a row spent using the tool) and their hearts (like lives remaining in a video game). Students earn experience points (XP) for their time in the app, and their user profile (visible when signed in) displays badges with their level and XP and flag icons representing the languages they're learning. Gems are another reward that can be used to change up avatars and other cosmetics. Additionally, students can see the number of words they've learned and level of mastery. The program's algorithm identifies  vocabulary words that require more practice as well as words that are cemented in long-term memory. 

Students can sign up on their own to use the Duolingo site (and Chrome app) or its corresponding mobile app (which is how most users access the service); both have free versions. A paid Duolingo Plus subscription removes ads, allows for offline courses (on mobile), and features targeted practice based on mistakes. Students can sign up for a Duolingo for Schools account, which is free, removes ads for students, and lets teachers link to their students' accounts and track their progress. Teachers can sign up for a free account, add class sections, and share a link with their students to let them sign up to join a particular section. Once students enroll, teachers can assign Skills lessons that target grammar and vocabulary or Stories to promote reading and listening comprehension. While browsing Skills lessons, teachers will be able to see the list of target vocabulary, making it easier to choose relevant work for students. Duolingo for Schools generates reports where teachers can see XP earned, time spent practicing, and progress toward assignment completion (with an overall course view or a detailed list view).

Duolingo breaks the complex details of language learning into manageable, meaningful chunks. Students don't just read about how a language works; they're guided step by step through exercises and get instant, detailed feedback as well as audio supports and contextual tips. The lessons use several methods to help students memorize vocabulary words, usage, verb conjugation, and other elements. There are limits to this approach, but good classroom implementation will fill in the gaps. Students view images to learn terms, translate sentences back and forth between languages, speak phrases aloud, and type phrases that a narrator reads aloud. If they make a mistake, they'll see the correct answer, and their responses help the system customize future lessons. Students can also opt out of sections if they're familiar with the material, making this an especially engaging, helpfully differentiated experience. 

Duolingo's comprehensiveness serves students with a range of abilities and language experience. The game-like features -- like experience points, hearts, and streaks -- can help make the tool rewarding and addicting in equal  measure. It'd be nice, however, to see more of this motivation focused on demonstration of learning, however. The teacher dashboard takes the experience to another level by allowing teachers to use what they know about students and/or language acquisition goals, to personalize individual, group, or class assignments. The progress tracker takes the experience a step further, turning scores into something meaningful and actionable for teachers. Although the data is somewhat limited and doesn't provide an in-depth view of student understanding and language acquisition progress, it's enough to get a realistic sense of students' time on task and completion of assignments -- correlating time spent practicing with skill improvement. Paired with teacher-led instruction, class dialogue, and in-person assessment, this is a rigorous, appealing tool for supporting language instruction at all levels.