>If you skip over the hard parts, then you're not exactly learning a language.
That's not true. Most native speaks have little knowledge of the grammar and syntax beyond intuitive. They have forgotten most of what they've been taught at school, plus, they could speak quite well before going to school and being taught grammar in the first place. We acquire language by osmosis, not by studying, and even less so by studying the syntax.
> Most native speaks have little knowledge of the grammar and syntax beyond intuitive.
The fact that they don't know the scientific names of the grammar rules doesn't mean that they don't know grammar. As somebody how's native language is very dissimilar to English, my intuitive language rules are no help speaking English. The grammar you are taught at school is descriptive of English and not a prescription. The distinction s very similar to "laws in physics". Nature doesn't really care about the rules we impose on it.
Learning grammar alone is not enough. Learning vocabulary alone is not enough. Immersing yourself to a language without a guide (like your parents guided you into language) is completely ineffective.
Grammar, vocabulary and pronunciation are equally important if you want to get fluent in both spoken and written communication in a different language.
>The fact that they don't know the scientific names of the grammar rules doesn't mean that they don't know grammar.
Similarly the fact that they don't study grammar and skip the "hard parts" doesn't mean that they don't pick up/know grammar, so the original argument is moot.
Apparently knowing grammar acts as a filter for bad speech, but it doesn't actually generate speech itself. Learning to speak is based on direct experience, not abstract rules.
That's not true. Most native speaks have little knowledge of the grammar and syntax beyond intuitive. They have forgotten most of what they've been taught at school, plus, they could speak quite well before going to school and being taught grammar in the first place. We acquire language by osmosis, not by studying, and even less so by studying the syntax.