"When you begin to think about what exactly you're trying to say, you become a writer." --Theodore A. Rees Cheney, GETTING THE WORDS RIGHT
If ellipses means to trail off (see September's THE SAMPLER), dashes flag "an abrupt switch or change." Sort of the yin and yang of dialogue, which includes both the spoken words or internalizations (thoughts) of characters.
Like all punctuation marks, a dash has a "sound of silence" (a certain length of pause) that a reader "hears" as they read and which helps a reader understand what's going on.
Let's look at common ways dashes are effective in dialogue passages and fiction:
1) The dash sets aside, like:
You know him–he's the guy who does the car commercials on TV–the one with three wives.
Now compare this to: You know him, he's the guy who does the car commercials on TV, the one with three wives.
Or: You know him–he's the guy who does the car commercials on TV, the one with three wives.
All are correct–but did you hear the difference in the delivery? There is a difference. A difference that results from the punctuation. (And if you didn't hear the differences? Well take the time to start really listening to how your characters speak–and listen to how real people talk. Or even close your eyes while watching TV and listen to your favorite characters speak.)
2) A dash can "show" stammering, hesitation, faltering by setting a string of words together like: I–I lost it. Or: I–I– I lost it.
3) The dash can show an abrupt switch of thought: He loves me–he loves me not! Compare this to: He loves me, he loves me not. Or: He loves me. He loves me not.
4) The dash also is used to show an abrupt interruption or cutting off, especially in spoken dialogue between two characters, like:
"You can't be serious, my boss would never—"
"Engage in an affair? Jeez, you're so naive!"
5) A dash often inserts vital information or adds an explanation for clarification: She killed him–shot him six times.
Keep in mind that a dash creates emphatic separation of words. It has a special forcefulness and should be used only when a deliberate effect is needed. Likely the most dash useage will be when a character is under stress, duress, or terrified. And dashes will be more prevalent with first-person and the deepest of third person narrative then any omniscient style of POV and Viewpoint.
When is a good time to make a pass through a manuscript for dash use or misuse? When it's time to make the last pass for punctuation. You do have a "cheat sheet" for revising your fiction, don't you? If your list of "punctuation to check for" doesn't include the dash, make it so.
Stop back on November 1 for a few words on Colons and semicolons.
Note: for some reason this didn't stay posted during October so I'm reposting it - Catherine