I was born in Ukraine, were I learned Ukrainian and Russian. Then we moved to Lebanon were I was able to pick up Arabic and English. I also know some German, French, & Polish. But the later are not on a level that I feel 100% comfortable working with. One field were I would have an upper hand on people who have learned this in School would be that the languages that I know I know them from the ground up, as I have learned them from locals with the exception of English.
I have learned my languages with the exception of English on the street; meaning that I know them as good as the locals of each country do, not less not more. My Arabic is on the level of the average Lebanese speaker, my Ukrainian is on the level of a Ukrainian, Russian is also almost perfect, and English is on a very high level.