French in the real world...
I'm trying to learn french and it's great fun to learn another language as it opens up so many doors both communication and career wise. But the thing i worry about most is that, even though i'm learning all these new words and phrases of standard french, how am i suppose to know what is acceptable and what isn't when speaking to actual french people who have spoken it all their life? there are so many different things which you have to be careful when saying so you don't offend anyone and I'm always worried that ill say something rude without meaning to.
Remember that the courses here are made by guys and girls like you and me so there should be a less academic feel to the wording. Another thing that I did was look for a French chat-pal via Skype. There are plenty of ppl out there wanting to do a language exchange and you learn VERY quickly doing it! There is a free site I once used called the Mixxer or something similar. I'm sorry I don't have the link, but a quick Google search should lead you right to it. Bonne chance!
Keep retaining words just from Duolingo, and if you want to get more use MEMRISE
You're learning standard French, as you point out. As a rule, you're going to be okay talking to French-speaking people. As far as concepts go, if you'd hesitate to talk about it in English, avoid it in French.