Save work in lesson to return to it later
It would be extremely helpful for me if I could save my work in a lesson in order to return to the same point later. The reason is that I'm using DuoLingo to help a disabled student learn English, and he works very slowly. We cannot complete a whole lesson in the half hour that I have to work with him. So when he exits, he loses all the work he did and has to do that material over again. So, within each lesson, it would be nice if there was a "Save & Exit" button, and the next time you clicked on that lesson, it would take you to where you left off. This would make it more accessible to people with disabilities.
This is not only helpful in case of disabilities, but also in case of poor connection. Some days ago I studied at Duolingo using an iPad with 3G connection. When I came almost to the end of the lesson, something went wrong with the connection, so when I hit the "Check" button nothing happened for a long time. And I could not refresh the page or tap this button again. If there were any saves, I would not have lost my work.