> I don't think I've ever come across a case where the error wasn't with a different tense or form of the verb. I.e., the sentence is structured a bit oddly, but it largely makes sense.

Oh come now. English, and I presume all natural languages, are replete with idiom for which it is virtually impossible for a non-native speaker to ever master. (E.g., "different from" is the correct idiom, while "different than" is not. But non-native speakers often mess up idioms that I didn't even realize were idiomatic until I hear a foreign speaker get them wrong. Things like "Put that at the table" rather than "on the table", etc.) If you learn a language after puberty, you will almost certainly never learn a language with the fluency of a native speaker. Something in our brains restructures itself after that point.

And this is why your claim is so insidious. If someone grows up in a poor community which speaks a different dialect of English from "Standard Written English", and they don't become fluent in Standard Written English before the age of puberty, they are likely screwed for life. They are biologically determined to NEVER master it to the degree that you require. But since you have a background in Linguistics, you must already know this.

This whole topic makes me rather depressed. It seems to me that anyone who promotes the idea that anything like perfect grammar is required to be a programmer--or anything other than an editor of some sort--is lacking in both compassion and ability to think scientifically. If you are willing to discriminate in hiring based on hypotheses for which there is ZERO scientific evidence, then you fail on both counts.

In fact, if I were to hire programmers, I think that instead I might test them on their abilities to be empathic and to think scientifically and logically, since these are skills that actually do matter for software engineers. Prescriptive grammarians would fail on all three counts.

By the way, do you have any idea how hard it was to get into and graduate from MIT being dyslexic? And yet now the world wants to add all these crazy hiring criteria hoops that I'm supposed to jump through??? Coding on whiteboards? Having perfect grammar? Doing handsprings and cartwheels? Haven't I proven myself enough already by getting into and graduating from one of the best and most difficult universities in the world, and then continuing on in a career with many commendable accomplishments? E.g., writing the software that configures an X-ray space telescope, and implementing the specificity scoring algorithm for RNA Interference hairpins; knowing how to program in a dozen-plus programming languages; etc. The increasing tendency towards myopic monoculture and inflexible hiring practices infuriates me. I consider it a personal attack on my mental and financial well-being. And it is!

Regarding your claim that "would of" makes no sense, I'm not sure how to jibe this with your claim of having a linguistics background. The first thing that one learns in Linguistics, which is the scientific study of how people actually do speak, as opposed to the unscientific field of prescriptive grammar, which aims to tell people how they ought to speak, is that if a community of people speak or write a certain way, then it always makes sense, and there is always a good cognitive reason for it.

That's not to say that the good cognitive reason always maximizes functionality, but the same criticism can certainly be made about prescriptive grammar too. A lot of the rules in prescriptive grammar are completely arbitrary, and don't reflect the real language, as actually spoken.

A clear example of this is the deprecation of double negatives. This prohibition is a modern invention, invented by Bishop Robert Lowth in 1762. Before that everyone in English said, "I don't have none", just as they do in Romance languages. There was nothing wrong with the sentence, "I don't have none" before 1762, and there is nothing wrong with it today, except to the extent with which you wish to distinguish yourself as part of the upper class. This cynical reason is the very reason that most of Lowth's silly invented rules were adopted by the upper class. There was nothing better about the way Lowth wanted people to speak compared to the way they had spoke before, other than as tool of class distinction.

Another example is the word "ain't". The sentence, "Ain't I a genius?" is actually grammatically correct. Contrast this with how most people now will say, "Aren't I a genius?" which is just plain wrong. Why do people make this mistake? Because prescriptive grammarians beat "ain't" out of them, which caused people to start using something wrong. Sure, now the "correct" thing to say is "Am I not a genius?" But what kind of pretentious idiot would say that?

As to what sense there is to be made of "would of" and "it's" vs "its": This clearly expresses a natural human tendency to desire a more phonetic written language. Spelling in English is just plain dumb. Don't take my word for it--just ask the great author George Bernard Shaw.

I have friends from Italy, and they tell me that there are no such things as spelling bees in Italy. I.e., if you know how to pronounce a word, you know how to spell it. What an enlightened language! Perhaps without having to devote so much of their brains to keeping track of the spellings of tens of thousands of words, they can use it for more productive endeavors. I guess I have no scientific evidence for this, but I do hear that Italians are better lovers. That's gotta count for something!

tldr: A pox on the anti-scientific prescriptivists and obstacle-course-of-arbitrariness-makers of the world.