While I'm not a huge fan of Duolingo, currently, it's the most convenient option for me. I actually started it for my trip to S. America two weeks ago, and since I started it, I figured I might as well finish it. I have ~100 lessons to go before finishing the whole course on Duolingo. This is going to take a while, a long while. I shall post screenshots of my progress from time-to-time. Hopefully someone bugs me if I don't progress:
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