Good news everybody! Run the DuoLingo Android app in Chrome
Having trouble posting links here... Let's see if I can post them as a comment...
Get the ARC Welder Chrome extension, https://www.addictivetips.com/ubuntu-linux-tips/run-android-apps-on-linux/ and then download the DuoLingo APK, https://www.apkmirror.com/apk/duolingo/duolingo-duolingo/duolingo-duolingo-3-57-0-release/duolingo-learn-languages-free-3-57-0-android-apk-download/download/ This allows you to run the DuoLingo Android app in Chrome. I just tried it on Ubuntu 17.04 and did a few Japanese units.