A user of - hopefully good - English rather than an expert grammaticist. An avid reader of books good, mediocre and indifferent for many years, I find myself able to use the language to convey my thoughts reasonably well.
In practice that means that although I usually know what reads, sounds and looks correct, explaining why it should be so is not one of my achievements. I have not the technical expertise I enjoyed - and I use the word in both senses - even as a schoolboy. I am in no way a professor or even a graduate; just a user. From birth. Nearly.