…that tourism can’t.
I had a few problems getting to Buenos Aires, and my Spanish underwent something of a baptism by fire. Quite simply, when the hotel receptionist at your second hotel tells you what time the shuttle is picking you up, you understand out of sheer desperation. (That was the second night in a hotel and hour 40-something of travel.)
Learning by necessity is one of those magic things. If you really, truly need to get something across, you will manage, and your language skills will get better for it. That happens much more often when you’re studying abroad. Why?
Because people who work on the tourist path also have a need to learn, but they’re learning English. When you go to Cancun or Barcelona, many people there speak Spanish and English, because the tourists only speak English. Very rarely is it necessary to speak Spanish, not in the desperate way I’m talking about.
Admittedly, the travel wasn’t fun (a fluke experience, I hope), and at the time I wasn’t particularly appreciative of the learning experience. But, oddly, my spoken Spanish is noticeably better after those two days of speaking it. If you stay where English is spoken, you speak English. If you go where there’s only Spanish…if you stay with a family that speaks Spanish…you pick it up pretty fast.