Make Me Welsh (BBC documentary)
I recently watched this documentary from 2015 and I'm so impressed with those kids! They went from knowing nothing to pretty much fluency in 12 weeks. It's incredible how fast they learn. It took me months to finish the tree at level 1.
It also made me wish my family had spoken to me in Okinawan when I was a child, as I feel it's very difficult to learn it now as an adult. It's a shame it's slowly dying out with very little interest in bringing it back to life :(
Oh, I think I remember watching that!
While 12 weeks doesn't seem like a lot, you have to remember that they were spending a lot of hours in those 12 weeks learning it. I don't remember exactly but if they were doing 6 hours a day, 5 days a week, then that would be 360 hours in total. If you do 1 hour every single day, that'll take you a whole year... and you're probably not doing it in an immersion environment either.
For comparison: Language A-levels are supposed to be 360 teaching hours and, where I currently live, language classes typically take around 120 hours per CEFR level (regardless of whether you do them intensively with multiple hours a day or more leisurely with only a few hours a week).
It is impressive how quickly we can learn languages given the right environment. I just wish we had more opportunities to do that.
You're completely right. Immersion is everything. I did a German intensive course in Berlin a few years ago and we all started at 0 and finished the B1 level in four months. We were all adults, so it is possible!
Still, going to school/uni after only 12 weeks of learning a new language is impressive.