If the clause forms a complete SV or SVO sentence that can stand on its own, the comma before the co-ordindate conjunction is required. This was mentioned upthread by Chessic Sense, as well as by my fourth grade teacher. The comma is optional and typically omitted for subordinate clauses.
Read what I posted again. Obviously I was referring to subordinating conjunctions, such as because, when, since, etc.
I agree that it is not adding any grammatical functionality, but all the style guides I am familiar with require or at least strongly prefer the comma before the “and” in the case of compound sentences, except in the case where the second clause is a brief one. The Purdue link given above is the guideline as I remember it from the Chicago Manual of Style and in my Associated Press Style guide. (“Use a comma if the subject of each clause is expressly stated: We are visiting Washington, and we also plan a side trip to Williamsburg. We visited Washington, and our senator greeted us personally. But no comma when the subject of the two clauses is the same and is not repeated in the second: We are visiting Washington and plan to see the White House.”)
Of course, the comma is only required if the dependent clause is first.
I guess should clarify my point. The way I see it, a clause, in and of itself, is neither dependent nor independent. It’s the introduction of certain conjunctions that makes any clause dependent. Or another way of looking at it: All clauses are independent, until a subordinating conjunction is involved.
But is it optional or proper in a trailing subordinate clause? For example, adding a conjunction to the sentence in the OP,
I didn’t get any presents this year, because everyone completely forgot my birthday.
I have a hard time deciding whether that looks ok.
“They” say you shouldn’t–or at least that it isn’t necessary, though I guess some editors would accept it as a way to emphasize a “pause,” particularly in quoted speech. However, if the subordinate clause could somehow propositionally restrict the meaning of the main clause–and that is not your intent–then a comma is necessary.
Am I really the first to suggest the following to help make it easier to remember? Perhaps I missed it.
It looks like you are, though there are only 27 posts so far. Why is this particular explanation any more preferable over the others?
Honestly? Because the phrase about the aunt with the hairy knuckles always stood out as particularly memorable for me. I used this to illustrate semicolon use to my young nieces and nephews. I figured the answers had been sufficiently explained to allow for a bit of goofiness. If I was mistaken, mea culpa.
Not at all. Anything that can make semi-colons amusing is especially welcome!
Absolutely not. That’s not what colons are for.
IANA expert, but this sounds whacko.
IMO: …
If a clause contains an explicit subject and verb, or subject, verb, and object, then it *can *be independent. If it lacks enough of those ingredients (IOW it’s a fragment) then it *must *be dependent.
I agree that a potentially-independent clause can be forced into dependency by a subordinating conjunction. But that doesn’t mean that all clauses are born independent.
e.g.
“I went to the store and bought some bread.”
I think you’d be hard-pressed to argue successfully that “bought some bread” is an independent clause able to be a successful separate sentence exactly as worded. The lack of an explicit subject is what makes it dependent; it has verb and object only.
Bought some bread–itself–is not a clause at all, so that’s not what we’re taking about. In this example, it’s part of a parallelism, so “technically” there’s an underlying clause implied, but in any case a phrase which results from a parallelism is neither subordinate nor dependent in the strict sense of those terms. When you take a subject out of a clause, that just makes it a phrase. That’s not the same thing as subordination.
If the clauses are short, you can probably get away with it. The best example is:
**
I came, I saw, I conquered. **
Otherwise, no.
My question to the OP’s friend: if not this, what IS the proper use of a semicolon?
It’s only reason for existence is to separate two independent clauses, to clue the reader to mentally reset his or her parser to expect an independent clause and not a dependent one. The longer the clauses, the more important this becomes.
Meanwhile, I recently read (on Facebook or some other universally acknowledged authority) “Never use a semicolon. Just don’t.”
Yeesh. It’s the Dumbing Down of English.
While formal grammar doesn’t allow separating independent clauses by a comma, it’s a very common practice in informal writing. I doubt I’ve even seen a semicolon in a modern paperback novel.
Only if beginning a sentence with a conjunction is allowed. Sure, I do it, but I know I’m breaking a grammatical rule when I do. Style trumps grammar.
A comma is not required. This is perfectly acceptable grammar:
I got up and I left.
The comma can be very helpful in removing ambiguous interpretations, and is especially useful as a parsing aid for longer clauses, but it’s not required.
Punctuation issues are definitely grammatical. Grammar is the set of rules to combine lexical elements together to form sentences or other grammatical constructs (e.g., clauses). Lexical elements include words and punctuation.
Right. It’s not required, though it can be recommended to improve clarity.
Bingo. This is also a case where a comma can be used to separate independent clauses: in a series:
I got up, I left, and I never returned.
You can do this with arbitrarily long clauses, though of course it becomes unwieldy at some point. (Cf James Joyce. 
)
Or, “I went to the store and I bought some bread.”
I don’t see how punctuation is included in lexicology (though I believe in a few very rate occasions they intersect). This issue has come up here before. From a strictly linguistic point of view, punctuation is not part of grammar, but is about written conventions which sometimes derive from it. Some people use the term “grammar” in a very loose way to include anything involving language, and I get that. But this particular concern–the comma splice–is more like a typographical error: putting in the wrong symbol. The language is otherwise grammatical. If someone is speaking, you’re not going to “hear” comma splice.
Like I said, the American English style guides I am familiar with and quoted from do want that comma before “and” in the case of compound sentences. It certainly was one of the questions in my Associated Press copyediting class. Now, do I truly think it’s necessary? No. But the style guides, in my experience, do want it, unless the following clause is short. (See the Purdue link and my AP quote. Unfortunately, “short” is not defined by these style guides.)
Also, see here under "compound sentences.
That’s the guideline as I’ve always known it. I would always put the comma in the “and I bought my bread” example. I tend to favor “open punctuation,” but this is one example where I’m conservative, as nobody would ever say it’s “wrong” to put the comma in, but leaving it out may be objectionable to some (if not many) grammar-type folks. And, no, the comma does not indicate a vocal pause. I don’t know why people think commas always mean a pause. They do not.
Well, not a literal “pause” in the sense that one imagines the speaker taking a break to have a sip of water before continuing, but a comma is a separator that aids comprehension by separating distinct ideas. This is important in long sentences with independent clauses, as already noted, but it’s also important in preventing word run-ins, a plague of the comma-averse that tends to render a sentence ambiguous or even change its meaning entirely. As, for instance, in the following real headline: “Rachael Ray finds inspiration in cooking her family and her dog”. A headline that could surely have benefited from a couple of commas.
My own view is that in a great many cases the use of the comma is arbitrary and should simply follow the cardinal rule of aiding comprehension, which is what all the other rules are really trying to achieve.
As to the OP, yes, absolutely, the semicolon is correct; the comma is annoyingly wrong. The only potential problem with a semicolon is that its use may be conspicuous in informal writing because it tends to be somewhat rare in that context. My own inclination in informal writing is to use the em-dash instead, but it’s not a practice that I particularly want to defend.