Being an academic, I often hang out with people of various nationalities, usually each with it's own english-based language, slightly modified by grammar quirks and foreign vocabulary. A linguist friend call that "international english", which I like quite a lot. After a while, you can play "guess the nationality" based on the grammar quirks.

And everyone is still easier to understand than Scottish people. :)

I got lucky in that I learned english not only by reading, but also by watching a lot of series (both american and british). Watching english series with english subtitles was a huge help for me, and I think it's a decent way to learn nowadays, much more effective than english classes.