Grammatical correctness is a big business there’s books and computer programmes to help people achieve perfect grammar because, let’s face it, there’s no way one person alone can possibly apply all those fiddly rules or notice every missing comma. What people don’t mention is that before the 19th century there was no such thing as standardised English and grammar was haphazard at best. If you’ve ever read an old novel and wondered why the paragraphs or sentences are so long, indeed why some of them go on for pages, it’s because the approach to grammar was ‘meh… sounds right.’
Why did standardised English come about? Basically it was a classist conspiracy against the poor. The wealthy could show their education with their ‘good’ English and ‘good’ grammar and sneer at the working class, their colloquial dialect and lack of education.
Despite this the rich worshipped working class poets, known as ‘peasant poets’ like John Clare. However, they seem to have done so in a performing monkey fashion. For a while he was fashionable paraded around as an astounding genius despite his lowly background until they got bored of him which, arguably, contributed to Clare ending his life in an asylum.
The problem of aiming for perfect grammar is that it denies freedom to play with language, perfect grammar does not incorporate the differences in language. I’ve never quite seen why, when you’re writing a novel in first person, the prose voice is expected to be different from the character’s speech. If a character is not grammatical, why should their prose be grammatical?
Does it matter if you know the terminology? No, you don’t need to know words like clause and adverb to form a sentence. I think the most important thing is that the sentence sounds right, that people can read it and that it says what you want to say, in the way you want to say it. We are, after all, writing fiction not academic essays or news articles.
I can think of books that violate grammatical rules, but these are literary books where language experiment as often been encouraged as if they’re doing something particularly clever, which never seems to apply to genre. That’s all beside the point though. I think when you are writing your story your first thought should be whether your sentence sounds right, not whether it’s grammatically perfect.
If the only limits on what you can write are your imagination then why should there be limits on how you write it?
That said, if you put apostrophes in the wrong place we will have a falling out.