Long story, BeeBee, but basically I had to learn it on my own in the late 70s because I always missed out English in class. First, I was born in Finland and chose Swedish instead of English, as an extra language (Swedish was far more useful in Finland, at the time, and I was born a native Finnish speaker).
Then, after moving to Sweden when I was 11, I discovered that everyone had to learn English and had been busy doing it for a couple of years by the time I came along. Me, I was busy learning Swedish and missed out even more English because of that. So, eventually I thought that I'd do it on my own instead, more or less.
I helped that my dad was an interpreter and I apparently got most of his language genes, but what really did it was reading Dr Jekyll and Mr Hyde.
I guess learning languages is pretty easy for me if I'm interested. Which is why I've always failed miserably trying to learn German...