Earlier quoted context omitted.
I have seen a lot of foreigners learning French (being French myself, and exposed to international students/professionals in various situations) and I have to seriously doubt that claim as well. I have seen some Americans learning French very fast, in a matter of 6 months, enough to be able to communicate and work in French on a daily basis, but there is no way they could be qualified as producing "clear, well-struct…
>> There's just so much the brain can absorb in a short time. Daniel Tammet learned Icelandic in one week. I would be interested to see what backs your claim that the brain can only absorb so much in a short time. I think both you and the GP are projecting YOUR limitations onto everyone else. The brain can and does absorb a massive amount of information each and every day. Training the conscious mind to direct that n…
Your point? Daniel Tammet is an autistic savant. And some people have eidetic memory. There is little relevance unless we find a method to recreate these traits in "normal" people, there is by no means any evidence that every human has latent super powers.
As a normal person having nevertheless high language aptitude, I reached C1 or very close to C1 in about 6-7 months. I say close to C1 despite reaching C1 level in a test, because I don't think it's fair to claim you have every capability for C1 as described by CEFR just because you passed a 4-hour test, in certain ways you just cheat by learning for the test. Anyway, even that was with a very generous amount of immersion, about a minimum of 8 hours a day including long hours of grammar practice. Still, despite praises from native speakers, at that time I wouldn't assert that I was fluent in speech or writing. Now to claim you can be "fluent" in 5 months just by studying 30-60 minutes a day is a bit outrageous.
I can't tell you how much our brain can really "absorb" and "retain" in one day, but there are very real limits in language acquisition after a certain age. I won't say it's impossible, but to realize your claims, we definitely need a magic pill or surgical operation / cybernetics.