6 ideas for improvement of Duolingo
There is a library of images, only used for the task "pick the X". How about sometimes displaying 4 images, and 5 labels in the language you want to learn and let the user drag the correct label to each image.
Another useful task could be displaying a list of words and then have the user associate each of them with the proper article (le/la der/die/das etc).
And for translation, how about showing a sentence and a suggested translation which with 80% probability contains a common beginner's mistake and have the user fix that mistake?
For better immersion, I'd suggest that the user interface texts ("Translate this text", "write what you hear" etc) after, say, one has reached level 4 would be written in the language you are learning rather than in the language you already know.
For the Android app: Include the "Tips & Notes" section found on the website, and when composing a sentence by clicking buttons with a word each, let it be possible to click a few millimeters above or below the button without those clicks being ignored.
I find that I am getting on very well with duolingo but when I come to say something in italian my mind goes blank. Could some of the exercises be amended so that they require a spoken answer? Thanks, and thanks to the people who put these courses together and made it possible for me to learn italian. Thanks.