Doulingo's homepage 

Simple and clean interface

Just like Duolingo is making the language learning process simple and easy, the interface of Duolingo is clean and easy to use. Basically, they adopt a white background color on the site and a black background on the app side, while users only have a few options.

Game like learning process

lesson page of Duolingo

Among the many comments that Duolingo receives, the top one is, learning on Duolingo is like playing a game. It responds to your actions, gives you feedback and encourages you to continue with them. Once you set up a daily goal, there is a line chart indicating the time that you spent learning. To learn a language, since it's something new to us, too often we don't want to get started. Another case is that it's very easy for us to stop learning. Duolingo offers a solution to help us get started. But that is not all. If you do stop learning with Duolingo but decide to get back later, you don't have to learn what's you always know. You can skip some lessons once you have passed a test from them.

Immersive learning experience

After you log in on their site, even if you type in keywords in google to get to the first page, it is where you left the last time. Let alone during the learning process, there is nothing else to distract your attention. What's more, it's more about vocabulary, but also improving the other skills, like listening, speaking, reading and writing. We mentioned that except for the sites, they also have apps for Android and iOS. This also comes in handy as users can start learning right where they left the last time.

A page of Duolingo during learning

So what can we learn from the UX design of Duolingo? The most important feature of Duolingo is its game-like design. This solves the pain of lots of language learners. It changed the traditional former way of learning language, where you need to learn and remember new words and phrases, and create a plan to review those by yourself, while very often there is no feedback.

If you are offering lessons to others, or in the scenario that you need to create tutorials for the users, keep in mind to make it as simple as you can for the users. If the steps could be designed like a game, that's great. But it doesn't always have to be that way.

Remember to allow the users to interact with you and try to respond to the user's actions. Other than that, offer a progress bar to show how far a user is from his goal to encourage them finish tasks and back to your site.