If you’ve never edited fiction and suddenly have to do a test edit for a small publisher of fiction and you desperately need to look up every dialogue situation possible right after you get the manuscript and panic that you actually don’t know whether that should be a comma or period, here’s the cheat sheet I wish I’d had—I mean, you could use… I didn’t need one, I knew all of this intuitively, of course!!!
This is based on CMOS 13.39 (“Direct Discourse”), though the “rules” about punctuation in speech tags are interpretations and, honestly, preferences. If you need a different style guide, you’ll have to go elsewhere (until I write one). I’m fairly certain most publishing companies use CMOS at least as a base, and if there are exceptions they will cover them in their own style guide.
A few examples of common dialogue situations:
Basics:
“I’m going to eat my shorts,” Mary said to Beth.
“Wow!” she said. “That is surprising.” (lowercase speech-tag pronoun after ! ?)
He said, “What is she going to do?”
I turned around. “She’s going to eat her shorts!” (no comma if action and not speech tag precedes dialogue)
“Now, Mary,” he said, “I want you to know this is a bad idea.” (comma all around with a full sentence is broken up by a speech tag)
“You think I care?” she replied. “What do I care what you think?” (cap for second part of dialogue if it’s a new sentence)
“I know.” He looked down and blinked back tears. (if an action instead of a speech tag follows dialogue, punctuate dialogue with period and then start next sentence with caps)
“I’m sorry…,”I said softly. (comma after ellipses before a speech tag)
“I do want to…” He trailed off as he turned away. (no comma if no speech tag).
“I hate you!” Beth suddenly screamed.
“What do you mean ‘I hate you’!?” he asked. (punctuation with quote-within-quote, ? & ! edition)
“She said you were ‘losing your edge,’” I replied for her. (punctuation with quote-within-quote, , or . edition)
Remember: If another character speaks or acts, it goes on a new line!
Interruptions:
He sighed, “It will never—” (em dash for interrupted dialogue)
“But maybe it could…,” she interrupted. (comma after ellipsis before speech tag; CMOS 13.41)
“Never,” he said, “say never.” (comma after speech tag & no cap when interrupting dialogue with speech tag)
“Never”—she stifled a sob—“say never.” (em dash for action interrupting sentence; CMOS 6.87)
Punctuation after dialogue/in speech tag:
“I will love you forever,” he said desperately. (no comma before adverb)
“I won’t,” she said, her brain throbbing in her skull. (concurrent action gets a comma)
“I know!” he yelled and slammed his fist on the table. (concurrent action with speech tag = no comma)
“I’ll wait,” he whispered, and ran out of the room. (non-concurrent action with speech tag = comma)
Long quotes:
Remember that there is no closing quotation mark until the quotation is done, even if it spans multiple paragraphs. There are starting quotation marks on every paragraph, though.
“This has got to be the worst day of my life. First I woke up on with a blistering headache. Then there was a bulldozer in my yard trying to push over my house to make way for a bypass.
“I didn’t even know they were going to MAKE a bypass! They’ve been hiding the plans at the back of the planning office basement, in a bathroom marked ‘beware of the leopard,’ in a locked filing cabinet.
“And now I’m lying in the mud in front of the bulldozer and my best friend is telling me he’s an alien and I need to come down to the pub because the world’s about to end.
“I swear to God, if I get abducted by aliens who read me terrible poetry I’m going to scream.”
(Credit to Douglas Adams)