Polish is too easy :)
I conquered the Polish skill tree in a couple of days. As a speaker of Russian (and Finnish, Hungarian, German, etc.) I could quite easily understand the Polish expressions, but now I cannot form even the simplest Polish sentence without several writing and inflection errors. This Duolingo course mostly consists of translations from Polish to English and clicking on images. That’s not enough. You must also train writing Polish sentences to become an active language user.
You mean serveral writing and inflection errors in English, isn´t it? At least I have this problem: I understand the polish sentence examples, but my knowledge of the English grammar is not as good as it should be and so often questions are marked as wrong (i. e. when I wrongly mix "a" and "an") although I had understood the meaning well. This is very annoying and time consuming, but I am afraid, this cannot be changed. On the other hand, doing courses from English into another language improves also my English a bit ;-)
Perhaps there will be a course from German into Polish (or Russian of course ;-) ) in the future.
That’s actually not what I mean. I wanted to say that I cannot write Polish after having finished this course, even though I can quite easily translate sentences from Polish into English. There should be more translation tasks from English into Polish to develop active language skills, too.
Ah, ok. I have the same problem as you and I decided to use a good textbook with deep grammar explanations, reading, writing and speaking exercises, which uses also original polish texts and naturally spoken dialogs to continue my studies and to improve my polish abilities, as I think, that the Duolingo system has done his job for me now.
Yes, I already do it, but the PL-EN course does not teach the polish grammar, as this is in fact an English course - even though there were more informations and I would be able to read and understand the polish explanations ;-) :-D (but in this case I wouldn't really need them ;-) )