Hmm yeah I guess it could be that they see this sound byte (quoting one scientist's opinion, not a study's results) as having answered the question. It's not reported to be the best way though, just what "Achieving fluency in the real world requires" (any at all?)

The article speaks of so much research but, if this is indeed the 'answer', uses nothing of it in answering the question. Could have just put that sound byte up top and saved themselves and us the further trouble...

Also, what's feedback even supposed to mean? Like Anki? Like having a speaker correct your grammar from the get-go as you speak, or do you speak a bunch first and learn by stumbling and do they correct major mistakes at first only? There's a million ways to fill meaning into these words. Sustained exposure is obvious, but none of the other words are any guide

Thank you!