That's what linguistics is. Grammar is as natural as walking. Almost everyone does it, and no conscious understanding of the rules is required.
I hate to nitpick, but this is not entirely true.
First, there is no innate, specific grammar or syntax in the human brain. Any given language -- even one's first language -- is learned. It's learned in stages, and true, one tends to pick up the rules by immersion before studying them consciously. But conscious study of the rules is extremely beneficial to improving one's understanding of, and facility with, a given language.
To say that "no conscious understanding of the rules is required" is a little like saying "Kobe Bryant is a naturally born basketball genius." True, Kobe Bryant may have certain athletic gifts and mental wiring that enable him to exceed 99.999999% of the world at basketball skill. But he learned the rules of the game, just like everyone else. And he practices daily. In fact, he probably practices harder than many of his less talented peers. Even someone of his natural endowments couldn't have risen to his level without conscious and repeated effort.
It's true that grammar and syntax start to seem natural and subconscious over time, especially as one improves in linguistic fluency. That's a good sign, in fact. But I've never met a writer who couldn't benefit from conscious study of the rules and fundamentals, even if only occasionally.
While I don't agree with theory, Chomskyian grammar actually does assert this. It has a certain intuitive strength behind it, too.
> To say that "no conscious understanding of the rules is required" is a little like saying "Kobe Bryant is a naturally born basketball genius."
Except that's different. "No conscious understanding" doesn't mean "no learning". Most English speakers easily use irregular pluralization without significant hiccups, but it's really just following I-mutation: http://www.etymonline.com/imutate.php I'll bet 99% of English speakers hadn't even heard the term or the concept.
Frankly, I'm largely responsible for this conflation. I didn't draw clear enough distinctions, and in fact, I probably lost sight of the distinctions myself in responding. That's 100% on me.
Nevertheless, the fact remains, a statement like "no conscious understanding of the rules is required" is overly broad and sweeping. It lends itself to about a thousand interpretations, mine being merely one of them. There are too many contexts for the expression of language, and methods of communication by which to express it (written, verbal, etc.), to make a categorical statement like that.
Could you speak to the relevance of the distinction?
> It lends itself to about a thousand interpretations, mine being merely one of them.
Could you offer some of them? I simply saw "an understanding of the rules, that is conscious, is not required". That seems like a simple enough, unambiguous statement.
I wonder where we got the idea that the only way people learn languages after their first is through school.
I think we have differing interpretations of "required"
What about my first sentence bugs you? The brain is certainly wired for language, but not for a specific language. English, for example, is not instinctive. A newborn baby will not spontaneously develop English; he will need to pick it up by being around others who are speaking it. Same goes for French, or Mandarin, or Russian, etc. I'm not going to spend all morning looking up and linking research papers on this topic, so I'll just need you to take a flyer on this. Either you're going to agree with me or disagree with me, and that's cool either way.
"I think we have differing interpretations of "required"
Perhaps, though it's probably not a semantic rabbit hole worth a deep dive. But sure, learning the rules of a language isn't technically "required" in order to attain basic fluency with the language. But conscious study of the rules is certainly required to break through plateaus in one's facility. I guess this ultimately boils down to what one's desired goals and outcome with a language are.
Either way, the statement "no conscious understanding of the rules is required" is overly reductive and sweeping.
Can you explain how the brain is "wired for language?" Naively, I would imagine language is just one instance of the general pattern "things Hierarchical Temporal Memory models (e.g. the neocortex) get for free given a large-enough training corpus." Is that what you meant, or is there actually some part of our brains that is specifically "language" and couldn't be repurposed for something else?
I think that's all Evbn was talking about. Most people aren't Kobe Bryant; most people don't have any desired outcome with their language skills.