Perhaps P is confused about the distinctions between "dialect", "idiolect", and "idiot". Or perhaps "idiot" means "dialect", in P's idiolect.
I know particularly aggressive pedants made linguistic rules unfashionable, but most of the time they are merely suggestions of how to get the most of language e. g. how to avoid ambiguities and get your meaning across. Sure, they aren't rules in the sense of constraining every single possible manifestation of language. But no one ever thought that. Not even the pedants: instead they believed that they should constrain every possible manifestation, which implies that they believed they don't.
A/an creates though my favorite technical copyediting conundrum, which is that of which version of the article to use for the subject "SQL query". Some readers will vocalize this as 'sequel query', others as 'ess-queue-ell query'. If you write 'an SQL query' you will seem illiterate to half your readers, while 'a SQL query' is just as jarring for the other half.
I've known some people who insist that punctuation is irrelevant, and they can understand written text perfectly well without it. And their reading speed does seem to be unaffected by the presence or absence of punctuation. But I generally find that while my reading speed is about the same as theirs for unpunctuated text, I read punctuated text faster than they do. Conventional punctuation helps those acquainted with the conventions to parse text.
As they are just conventions, they will inevitably change over time. For example, it seems to be increasingly common to link two main clauses with a comma. Outside certain rhetorical and poetical usages, I find this jarring. But I may already be in a minority, and at some point in the not too distant future, it may not merit comment at all, except in the rantings of rules-fixated, traditionalist grammarians and would-be grammarians.
I recommend _The Linguistics of Punctuation_, by Geoffrey Nunberg. It's a linguistically-informed descriptive (rather than prescriptive) analysis of English punctuation.
That would be you, apparently, calling people idiots for breaking what you call the only real rule you can think of.
Note that this is called a guide. Some of the rules are just convention, but many make the writing easier to follow, and some can help avoid ambiguity.
Even in the cases where it is merely a matter of convention, significant variance might be creative, but it is more likely to be taken as a signal that you haven't read much (allowance should be made for those for whom the language in question is not their native tongue.)
I dipped into this guide, and it seemed to be written in a very straightforward manner - take a look at the section on the differences between British and American punctuation, for example.
The reason "an" exists is because it is quite hard to say things like "a elephant". Much easier to say "an elephant". Similarly it's quite hard to say "a 'istoric occasion" - much easier to say "an 'istoric occasion".
However since we now say "historic", not "'istoric", it is much easier to say "a historic occasion" than "an historic occasion". For some reason this (and only this) combination has been repeated enough that people over-correct and think that there must be some rule that they never learnt that dictates that it is "an historic". They don't really consider why "an" exists.
Nobody ever says "Tomorrow I have an history lesson."
Anyway, that's about the only 'rule' I can think of that doesn't really have any exceptions.
The baseline is to try to produce something that can be understood by your public, so try to stick to whatever convention they are used to, or come up with new ways that they can make a sense of.
But I won't even call that a "rule".
I don't think it needs to be exact, but an effort to express things accurately should be made. If I say, "Fish garbanzo bean flunky jellybean!" It is quite reasonable for you to say, "No, that isn't the name of an ocean."
If I continue doing so, then I would expect to be excluded from the conversation.
Really? Isn't that a bit broad? It may be half true for some languages but definitely not for all.
For example in Germany we have the "Der Duden" which is not only a dictionary that defines the correct spelling of words but also contains a huge set of grammatical rules. It's still the de-facto standard for correct language in German.
And even in english you'd probably agree that there are some rules, e.g. when it comes to the correct spelling of words.
Linguists on the other hand have given up on prescriptivism decades ago. Scientific linguistics are entirely descriptivist, studying how language is used rather than prescribing how it ought to be used.
> When used in this way, the bracketed information should be an addition, not a substitution. For example, if the original quotation is “She never called back,” do not change it to “[Lucy] never called back.” Instead write: “She [Lucy] never called back.” (Note: Many newspapers ignore this rule. In professional and academic writing, it is better to follow it.)
Says who?
About the only real "rule" I can think of in English is that you use "an" iff the following word starts with a vowel sound. But even some people (idiots) break that rule for the weirdly specific case of 'historic'.