galoisien

Linguists would object to this statement.

All native speakers subconsciously are intimate with all aspects of their native language's grammar -- excluding variants and dialects which they might be alien to.

However, only a considerable minority bother to *analyse* why grammar behaves the way it does and analysis skills are required to *repair* broken sentences. The other thing is that it's not so much as memorising prescriptivist rules as using one's analytical skills to achieve a consonance across sometimes conflicting principles (for example, strict agreement versus concord). Why do grammatical errors occur? Basically, we create grammatical thought phrases but due to the fleeting nature of thought we often change what's in working memory -- what the "that sounds right to my ear" mechanism draws from. With sufficiently large essays, working memory that has erased the structure of construction A to make room fo construction B might not realise that there is disharmony between both constructions.

That is when analytical and proofreading skills come in.

Anyone who asserts that many people do not know the rules of grammar, or that most people often are unaware of some obscure inkhorn prescription and are therefore unaware of some specific point of grammar, is a subscriber to prescriptivist poppycock, as George Pullum of Language Log would say. (Language Log by the way, is a blog comprised of many famous well-published linguists ...)

I apologise for the multiple nested clauses. What makes some texts harder to read? It's the fact that a particular construction may not fit in working memory (of the shortest term) and therefore we have to break it apart into smaller constructions and fit the ones not in working memory in a sort of inconvenient "swap". Thus usually a construction might unconsciously be processed several times (even if you think you're going over it once) as the already processed parts of the construction are compressed and finally re-assembled in working memory as a compilation of "pointers" to other locations within memory (where the "real" portions of the construction are being shipped off to).

Again, it's never about memorising the rules of grammar. It's developing the analytical skills of language. Most people know how to read and internalise a book, but less than a majority perhaps, might be fit to critically analyse it.