It's the same as almost anything, learning to walk, learning to talk, learning to drive a car. Eventually, information gets pushed into your subconscious, and instead of fighting with every new piece, you take some of the pieces of information as real and don't question them any more. This reduces creativity, but makes you more 'productive' (you essentially become better at pushing symbols, rather than thinking of what symbols could be). When it's in your subconscious, that's one less thing you have to juggle to get further. When you're stuck on syntax, you can't really make full sentences. When you're able to complete full sentences, you're able to write novels, or this comment.