Languages morph over time, and English is able to handle the change. I remember in an English Lit class having to read the opening to Chaucer's Canterbury Tales in Middle English. The opening four lines were:
Whan that April, with his shoures soote
The droughte of March hath perced to the roote
And bathed every veyne in swich licour
Of which vertu engendered is the flour;
(Wow, that took some serious over-riding of the spell checker to type!)
That opening was pronounced (roughly)
Vaan that A-pril, with his shoe-ers swet
The drachts of March hath per-ced to the root
And both-ed every veen in swish liquor
Of whose vir-two, on-jon-red is the flur
In modern English that opening becomes
When April with its showers sweet
The drought of March has pierced to the root
And bathed every vein in such liquor
Of whose virus engendered is the flower
So I get it, languages change. But what annoys me is not so much the incorrect use of there/their/they're or its/it's or you're/your or a misplaced apostrophe. Those I just laugh at and read through them when they are online. They reflect badly on the writer as a sloppy thinker, to be sure, but sometimes a
spill chicker will jump up and change things that go unnoticed. In a book, however, it's most annoying when I hit a grammatical error because those errors signal that the proofreader did not execute the task properly. Given that the proofreader was paid to correct the mistakes, that failure signals that the proofing was done poorly and in any non-fiction book puts the rest of the book in the precarious position of mistrust. If the publisher cannot take the time to get simple grammar correct, why should I trust the point of the rest of the material? Was the writers thinking so poorly organized that the proofreader had no chance of getting it correct? Bad grammar is, to me, a signal of potentially equally poor logic or thought. Not always, I understand, but it does weaken the impact of the author's logic and my trust of it.
What drive me over the edge, however, is the lack of punctuation. When someone comes to this forum and starts to tell us all about the problems with the system they are having and run everything together with no breaks and no punctuation I find it very hard to read often I don't bother to read past the first line or two because I simply don't have the time to try to sort out what they might be trying to say It is hard to read much less understand. I want to type out an answer something like
.....,,,,,,;;;;;:::: Sprinkle some of these in your post so I can tell what you are trying to say.
& don't u txt 2 me unless u r on ur fone. Not English. Twittering, maybe. English, no. You have a full sized keyboard, use it.