I'm not trying to be dense, but I still don't see it. Punctuation helps with identifying boundaries of clauses, whether they're dependent or not, whether a sentence is a question. Is this what NLP struggles with? I don't think so. One of the big unsolved problems is understanding the referents of pronouns (and other proforms, like "I will [do so] too"). Style guides and generally prescriptivism does not help that.
Another ambiguity is parse ambiguities like " I saw the girl with the telescope." What does "formal" English say about that?
>I don't think there is anything "formal" about Standard English.
"Standard" English as she is spoke? No. But a3n was specifically talking about the formal version often called "Standard written English". It is very prescriptive and less flexible, which makes it easier to parse.
> Can you give an example of what you're talking about? Which grammatical rules do you have in mind?
Let's start with "every rule involving punctuation".