Something that distinguishes child-rearing and immersive language learning from children in school is the seriousness that both tasks force. The parents want to create a new, well-functioning human being (when they don’t want this, it doesn’t go well), and you need the language in order to have any interaction with the people around you. At least, you do if you’re a newborn, and it still takes a good many years. (Is immersion actually the best way for adults? It’s the only way for children, but because of that there’s no other way to compare it with.)
That quality of seriousness, it seems to me, is what produces progress. The school child is rarely serious. Someone attending a course just for the socialising is not serious. There are teenagers who have won gold medals at the Olympics. Those ones are serious.
Something that distinguishes child-rearing and immersive language learning from children in school is the seriousness that both tasks force. The parents want to create a new, well-functioning human being (when they don’t want this, it doesn’t go well), and you need the language in order to have any interaction with the people around you. At least, you do if you’re a newborn, and it still takes a good many years. (Is immersion actually the best way for adults? It’s the only way for children, but because of that there’s no other way to compare it with.)
That quality of seriousness, it seems to me, is what produces progress. The school child is rarely serious. Someone attending a course just for the socialising is not serious. There are teenagers who have won gold medals at the Olympics. Those ones are serious.