I joined Second Life with another account in 2007. At the beggining I used to spend time with other Spaniards who were into some Naruto roleplay sim. I got bored of it and shifted into the SLMC, which is... basically shooting prims at people using LLCS. Most of the groups that did that spoke English; they were kind enough to let me in despite my non-existent English. Around 2009 I began to talk to them on Ventrilo and Teamspeak.
As time passed I learned more and more, just by being around people, reading and listening; but I still struggle with some accents and vocabulary I'm not used to hear. But yeah. I learned English on Second Life.