Speak Portuguese and Learning English?
Although this is common knowledge it may still be news to one or two people.
If the only reason you have chosen the Portuguese option is to learn English, you are missing out because you can actually learn English via Portuguese here!
All you need to do is edit your profile (click on the gearwheel icon on the Duolingo banner and select "Settings"). On the account tab you'll see a pull-down menu which says "Learning Language", select "Quero aprender Inglês (eu sei Português)" and then click "Save changes" and you are done. (When you do that you will only see the English tree. If you want to see your other trees you'll need to revert to your current selection.)
What you gain by doing this are speech exercises which test your ability to speak English; all the audio, including transcription exercise audio, is in English, not Portuguese and finally, the discussions, usually conducted in Portuguese, are often much more lively than the ones in the Portuguese via English section.