Originally Posted By: Andrew Robinson
...but I have always regarded punctuation as an essential element of grammar. Of course this is a recent development, tied to writing rather than speech, but very important, and now surely indispensable.

It is sometimes connected, as for example in the possessive apostrophe, especially in the neuter singular, it's v. its - that is a case of the two being intertwined. But I would tend to agree with zmjezhd, generally speaking they are distinct entities.