This is a good explanation as to why many people believe that immersion is the best method for language learning. Because you're constantly exposed, a lot of what you learn is unconscious and you can learn much faster - plus you actually need to use it to get by in day-to-day life.

This is a fascinating example of procedural knowledge in English that I'm very surprised native speakers don't think about (myself included). I didn't even realize that this was a grammar rule until maybe two or three years ago. It makes me wonder what makes something a grammar rule what doesn't. Is there a reason adjectives are ordered this way?

I think that this method would only be truly beneficial for learning how to speak without an accent - which isn't a bad thing at all, but there isn't much use for that skill without the grammar or vocabulary knowledge to actually go beyond parroting exactly what you've heard before.

I think this is why a lot of people struggle to actually learn when only doing something like Duolingo. I've tried that route before, and I barely remember anything that I learned from attempting to learn solely through apps - people overestimate their skills even though they probably have never actually used the language in real life.

I think for native English speakers, in most cases motivation has to be intrinsic to fully learn another language. Because there isn't really a need for English speakers to know a second language, especially in the United States, unless you really, truly want to learn for the sake of it, whatever you learn won't stick.

I think the fact that people have a tendency to fall into a fixed mindset as they grow older is not because they can't learn new things, but they simply don't see a need to. When a child is learning their first language, it's necessary to function in society, so they have to learn. For an older child or adult who is learning a second language, such as in a classroom, there isn't really a necessity to use it outside of that environment, so when they fail to retain what they've learned, if they see no reason to keep trying then they simply won't.

People often don't realize that the high standards they set for themselves aren't realistic. It's much more common people to set a high bar for themselves, than for other people to impose such expectations on learners, and they don't know how ridiculous they're being. I think this true for language learning and many other aspects of life.

I would argue that this idea and the idea that adults can learn a language completely from scratch can coexist. An adult can become fluent in another language, but they will likely have more difficulty learning a language than a child because a young child will most likely learn their second language the same way they learn their first: immersion. That's why it's often suggested to immerse yourself in your target language - it's how children learn.