Perhaps I have not advanced far enough in the program yet but are there more variations in Duolingo's speaking exercises? For example, I would find it very helpful if sentences were written in English and the listener were to respond in whatever language they were studying. That way the learner must translate and speak instead of simply parroting back to the program. Does this exist in Duolingo?
The problem with that is that there are variations with the translation. The computer has trouble trying to understand what it expects you to say, making it try to decipher variations would take a lot of work.