Well, most of what you say is true, but doesn't require immersion. For example, I have Israeli friends here in the States, and I keep in touch with a couple co

Well, most of what you say is true, but doesn't require immersion. For example, I have Israeli friends here in the States, and I keep in touch with a couple cousins in Israel. So it's possible for me to have real conversations (as opposed to contrived conversations with classmates or workbook exercises etc.) without actually going to Israel. I found immersion useful because when you hear a language all day, every day, it seems to seep into your subconscious. Also, I think that language learning is a function of density rather than just volume, so to speak. That is to say, spending ten hours speaking a language every day for a month is more effective than speaking it for half an hour a day for 600 days.