The basics: punctuation goes inside the quotation marks
In U.S. English, commas and periods always go inside the closing quotation mark. This rule applies regardless of whether the punctuation belongs to the quoted sentence or the surrounding text.
"I noticed the mistake," she said. Not: "I noticed the mistake", she said. This is the most common dialogue punctuation error in manuscripts, and it is an easy fix once you know the rule.
Dialogue tags: use a comma, not a period
A dialogue tag (said, asked, whispered, shouted) is grammatically part of the same sentence as the dialogue. When a tag follows a line of speech, the dialogue ends with a comma, not a period.
"I will be there soon," he said. The dialogue tag is not capitalized because it is a continuation of the sentence, not a new one.
"Where are you going?" she asked. Question marks and exclamation marks replace the comma, but the tag still starts lowercase.
The mistake to watch for: "I will be there soon." He said. This treats the tag as a separate sentence, which is grammatically wrong.
Action beats: use a period, not a comma
An action beat is a character action attached to dialogue. Unlike a tag, it is a separate sentence. The dialogue ends with terminal punctuation (period, question mark, exclamation mark), and the action beat starts with a capital letter.
"I will be there soon." He grabbed his coat. "Grabbed" is an action, not a speech verb, so it is a new sentence.
The most common mistake: "I will be there soon," he grabbed his coat. This creates a comma splice because the action beat is an independent clause masquerading as a dialogue tag.
The dividing line is simple: if the verb describes how the words are spoken (said, asked, whispered, shouted, muttered), it is a tag and takes a comma. If the verb describes a physical action (grabbed, walked, sighed, nodded), it is a beat and takes a period.
Em dashes for interruptions
When speech is cut off abruptly — by another character, by an action, or by the speaker stopping themselves — use an em dash inside the quotation marks.
"I was trying to tell you—" "Save it." The em dash signals an abrupt cut. Do not use an ellipsis here; ellipses mean trailing off, not interruption.
"If you would just listen to—" The door slammed. The em dash again shows the speech being interrupted, this time by an event.
Ellipses for trailing off
When a character trails off, loses their train of thought, or hesitates, use an ellipsis. The character is choosing to stop speaking, not being interrupted.
"I thought we were..." She looked away. The ellipsis shows the character deciding not to finish the sentence.
The distinction matters: an em dash is forceful and sudden; an ellipsis is gradual and quiet. Mixing them up changes the emotional register of the scene.
Multi-paragraph dialogue
When a single character speaks for multiple paragraphs, do not close the quotation marks at the end of the first paragraph. Open each continuation paragraph with a quotation mark, but only close the marks at the very end of the final paragraph.
This convention exists to signal to the reader that the same person is still speaking. It is fairly rare in modern fiction, where long speeches tend to be broken up by action beats or other characters' reactions.
When fiction can bend these rules
Not every rule is absolute in fiction. Some writers deliberately omit quotation marks for stylized effect. Others use comma splices in dialogue to capture the rushed texture of real speech. What matters is whether the choice is intentional and consistent.
The general principle: break the rules on purpose, with awareness, and for an effect the reader can feel. If a reader is confused rather than drawn in, the rule-break is not working.
The danger of rule-breaking is that it can look like a mistake rather than a choice. Using a proofreading tool that understands fiction conventions helps you fix the actual errors while preserving the deliberate ones.