Learning Spanish, teaching Hebrew, making friends
Language exchange isn't a classroom. It's the fastest way I know to enter the social life of a new city.
There's a chasm between sitting in a classroom and sitting in a bar trying to explain to someone from Argentina what 'firgun' means (the Hebrew word for the joy of celebrating someone else's success). In the second case, you both end up laughing, and within an hour you're having a real conversation about something.
The format of a language-exchange meetup is brilliantly simple: half an hour in language A, half an hour in language B, and in between — just two humans clicking.
After six months of showing up, I have vocabulary I never dreamed I'd learn — and, more importantly, I have friends across the country. They call to tell me about a new film, they invite me to weddings, and sometimes they even correct my grammar.
One recommendation: don't pick a community based on the language you want to learn. Pick it based on the people you want to meet.