How to swop english <-> german?
I am native german, so I should translate into german, not into english, right?
I believe this software works in both directions, so you will be able to contribute and also improve your English. One tip: for "oder?", use "right?" at the end of a sentence. :-)
You will be very useful here. This is how this site works. You should translate as many as you can and correct other peoples' translations. And it will definitely be useful for you because as mowamowabobobo said it will work in both directions, so you can improve your english :D
Translate into english!
As far as I know you can't translate into German, at least not yet. Currently, Duolingo is offering only non-English->English translation practice, because the site is geared for English speakers.