Just off the top of my head: In some US dialects, rather than a single word changing between negative and positive form (e.g. “I didn’t take any pictures”), instead an entire sentence is shifted into a negative mode (“I didn’t take no pictures”). Traditional grammar rules would dictate that as a double negative, implying the speaker did in fact take pictures, but only an idiot would actually choose interpret it that way.

Next, we have the impact of the internet. “lol” might occasionally be spoken aloud in many circumstances as a substitute for “that’s funny” or something similar. Colloquial written English is all over the place. We now not only use “lol”, but “fwiw,” “afaik,” and many others.

Then there’s emoji. We’re basically using glyphs to express ideas, not unlike how kanji works, and traditional rules of grammar don’t always apply when you’re expressing an idea through pictures, though it’s interesting when it does. Animated GIFs and memes often butcher grammar rules without sacrificing any understanding of intent.

A simple google search turns up many more examples than I could possibly be aware of.

Now it’s your turn. Feel free to explain why you think using “they” as a singular pronoun applies as a grammar rule violation in the 21st century. If you can’t use more than a typical snarky one or two-liner, you should just consider this argument lost and rethink your life.

Ironically, one of the biggest changes from Shakespeare’s time and now concerned pronouns. We stopped using “thou/thee” as the informal 2nd person and began to only use what had been the formal 2nd person, “you,” and stopped using the verb conjugations for them.

Meanwhile, the 3rd person singular “they” has been in use since Chaucer’s time.