And no, I do not accept the notion that grammar rules are "artificial" and "arbitrary" — imposed by the elites of society. What utter nonsense. The British nobility adopted a lower-class pronunciation pattern over the last century. Don't try to claim they did this to hijack the language from the poor.
Some neuro-linguists (Pinker, certainly), point out that these rules are not as arbitrary as they seem. He charted "irregular" verbs and discovered logical and predictable rules from earlier languages. (I love such forensic linguistics.) English is dozens, if not hundreds, of languages and dialects blended together. The symbols we use are artificial, but the sound patterns are not. Even chimpanzees have a complex "grammar" that forms short sentences (de Waal). Vowel shifts and consonant changes that occurred over centuries of time have rendered English and French less phonetic than Spanish, as an example, making spelling a nightmare for students. I proudly defend "proper" English... celebrating how wonderfully mucked up the language is by centuries of stealing words, structures, and pronunciation patterns from every other language on Earth. There is no purity in English, thank goodness.
Still, we need rules. They help us communicate with a tad less confusion. Only a tad, but that's something.