This has been explored in linguistics. People do have an innate sense of grammar. However, language use changes over time, of course, and it's absurd to try to prevent that. Here's a good example -- as you said above, "People just know how to speak right." Of course, many English teachers would love to tell you that you're supposed to say "speak correctly" -- but why? It's a widely understood use of the word "right" and most people wouldn't think anything of it. Having standards about written language are necessary and helpful, but arbitrarily dictating the use of words based on their history is not necessary or helpful.

>> However, language use changes over time, of course, and it's absurd to try to prevent that.

I agree, totally. Different people have a different sense of what is right and wrong to say. I'm guessing that is how languages change over time.

But the fact remains that there are things that are very likely to be nearly universally received as wrong. For example, if I say "My mother will eats here tonight" - most people will wonder why I don't say "eat", etc.

Equally, hearing or reading someone use a pronoun like "ey" or "zie" that are not part of what the majority of English speakers will recognise as English is likely to raise an objection from many. I assume listeners or readers who have only a fleeting familiarity with non-binary people, though this may be a bit unrealistic, given the internet etc.