I showed the site to students in September as a way to work on Spanish independently on their own time. Students do also have the option to use Duolingo in class on Choice Time days (which I will discuss in more detail in a future post). I have never assigned it as homework, as it is optional to use. In addition to learning Spanish, various students have started learning other languages including French and Italian. One student told me how her family is using it now and they have a competition going. Another student started learning French with it and sought out French instruction on Saturdays to complement his learning. There are many more stories, but you get the idea! I think it provides a great opportunity for students who love learning languages or need an opportunity to review material to do so at their own pace.
Are you using Duolingo or similar resource you like?