Sometimes, writers make stylistic choices. e e cummings and James Joyce are probably extreme examples, but you get the point. In the end, all that mattered was that people could get used to what they were doing, because it was consistent. It was still readable, because it followed some sort of pattern - however undefinable.
For some reason, a lot of the writers I've worked with can't figure out the basics of dialogue and how to punctuate it. And when questioned about it, they almost always go for the "stylistic choice" argument, when really, it's just because they're afraid to admit they have no idea how to do it correctly.
Well, good news! We're going to talk the basics of dialogue punctuation today.
Here's the easist example: Sally said, "John, tell the class your name."
OK, let's break it down. Sally said is the attribution. This is the part of dialogue where we put which character is talking. Generally speaking, we use the verb "said" to do this. Said, when the attribution is first, is followed by a comma, then the start of the quote. Notice the spacing here, too: no space after "said" and before the quote start, but a space before the first quotation mark.
Whatever the character is saying is surrounded by two sets of quotation marks, one to mark the beginning of the talking and one to mark the end. Notice that there can be punctuation, as normal, inside the quotation mark. In our example, the comma after "John" doesn't change just because it's inside the quotation marks.
At the end of the quote, since this is the end of our sentence, we put a period inside the quotation mark. This is an area of common mistakes, as sometimes people will put commas inside and periods outside.
Let's take a look at another example, if the attribution is after the quote: "John, tell the class your name," Sally said.
Notice that the parts of the sentence are the same, but the punctuation has changed. Inside the quotation marks, there is now a comma. This is a replacement for our original period, signifying the end of a complete sentence inside the quotation marks. Our period moves to the end of the sentence.
And once again, the punctuation inside the quotation is standard - the quotation marks don't change other grammar rules.
So what about question marks and exclamation marks, then?
Question Mark: Jake asked Molly, "Would you like to go out with me?"
Exclamation Point: "Run for your lives!" Elizabeth shouted.
These two work pretty much the same way and in a very similiar way to the period. Just like before, the sentence-ending punctuation of the question mark ends the sentence. There's no need to put another period after the quotation mark. Also, notice that I put "Molly" after the "said", even though Jake was speaking. That's fine, as long as you have that comma before the first quotation mark.
In the second example, we have our sentence-ending punctuation in the form of an exclamation mark. Here, we do need a period - but only after the entire sentence has been completed, so after our attribution.
Attributions don't have to always be given, as long as it is clear to the reader who is speaking.
For example: Darla wanted to say what she was feeling, so she walked up to the mike. "I hate you all."
It's fairly certain, especially if other characters haven't been mentioned recently, that Darla is the one saying, "I hate you all." Technically, there is no attribution here, and we use our punctuation to show that the quote itself is a complete sentence with a period at the end.
So, those are your dialogue basics, and should actually get you through about 75% of your dialogue needs. So no more saying that your lack of commas is a stylistic choice.