I think Duolingo is FANTASTIC as a resource for language teachers and have started using it with my High School French and Spanish classes, encouraging my colleagues to do the same.
The ONLY improvement I would like to see is the ability to ASSIGN a specific area of language for students to explore (in addition to their own self-directed activities).
For example, if I want my learners to review adjectives, I would want the ability to assign that topic (even if already completed by a student).
For students who have already worked through that particular topic, a "test out" could be offered that would allow them to quickly demonstrate their learning and continue with their modules at their own pace.
This would allow teachers to, at a glance, see an up-to-date list of where learner abilities lie in a particular language theme, and also determine that students are actively engaged in course contents or reviewing areas of weakness as determined by the course instructor.
This could be achieved through a "test" feature, or "test-out" feature, providing a unique series of questions/tasks that could be assigned by the teacher from the Dashboard.
I find Duolingo to be a FANTASTIC option for the flipped-classroom!
Thank you all for your hard work and openness to suggestions!
This is a good idea and we are aware that teachers are with you on this one. There are technical issues that complicate things a bit on our side (especially when it comes to assigning a skill that has not been reached), but we are looking into solutions and improvements to make Duolingo an increasingly more helpful companion for teachers. Duolingo is constantly evolving based on classroom observations and educator feedback, so thank you for sharing and keep these suggestions coming! :]