>>718330527
You would be surprised, honestly. Kids pick up on grammar pretty quickly and they're just exposed to the gamut of natural conversation from birth, so by the time they're five or six, while they won't be perfect they'll probably have an intuitive grasp of 90-95% of the grammar applicable to ordinary fiction, but they haven't had time to develop a comprehensive vocabulary.
Adult language learners tend to come from the opposite direction of having a passable vocabulary much earlier than their grammar skills progress to the level you'll need for anything more advanced than "Spot the Dog" or textbook examples and set phrases.
It's a lot easier for an adult to just memorize lists of stuff than it is for basically anybody to understand and be able to use a flexible system like grammar.
