What does a dash indicate in dialogue?
To show an interruption of the spoken words, include an em dash inside the quotation marks, at the point where the dialogue is interrupted. “I knew you'd drop it.”
A dash is a horizontal line that shows a pause or break in meaning, or that represents missing words or letters. Note that dashes are rather informal and should be used carefully in writing. Dashes are often used informally instead of commas, colons and brackets.
Like a colon, a dash can be used to introduce an explanation or restatement in place of expressions such as that is, in other words, or namely. Begin the clause after the dash with a lowercase letter. The reporter relentlessly pursued the woman— he was determined to get her to make a statement.
Use dashes to set off an idea or an appositive within a sentence. A dash (—) is a punctuation mark used to set off an idea within a sentence and may be used alone or in pairs. Dashes interrupt a thought in a more dramatic way than a phrase enclosed in commas, but less theatrically than parentheses.
Dashes (—) in Shakespeare indicate that the character is changing who s/he is speaking to. The changes for an actor are similar to those needed with parenthetical statements. Always look to understand the new thought in connection to the thru-thought or thought that comes before the dash.
To set off material for emphasis.
Dashes can be used for emphasis in several ways: A single dash can emphasize material at the beginning or end of a sentence.
The Dash. An em dash—inserted by typing Control+Alt+Minus between the words it separates—signals an abrupt break in thought. It can be seen as “surprising” the reader with information. If used judiciously it can mark a longer, more dramatic pause and provide more emphasis than a comma can.
1. Dashes. Quick Use: Use a dash to connect independent clauses or to inerrupt a main clause in a way that creates dramatic effect. Dashes function in two ways: to signal interruptions in a sentence (basically like parentheses), and to connect independent clauses.
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Keyboard special characters.
Aposiopesis is a term where a sentence is purposely left incomplete through the use of an em dash or ellipsis.
How are dashes used in narrative writing?
Basically when a character is cut off in dialogue (or in some cases, even thoughts), you should indicate that with an em dash. If action interrupts a complete sentence of dialogue, you set it off by em dashes: "You said"--she wrenched open the car door--"that she would be safe!"
The dashes create an emphasis on parts of the sentence and take on the role of either commas or parentheses. When she uses the dashes as commas like the stanza from above it shifts the focus on the words that follow the dash, so the phrase “that oppresses” is meant to resonate with the reader.

Using an em dash in place of a comma
Em dashes can be used in pairs to replace commas when writing a parenthetical or interruptive phrase. The dashes have a slightly more emphatic feel, making the reader focus on the information that is set inside the special marks.
The dash (—), also called the em dash, is the long horizontal bar, much longer than a hyphen.
A dash is a punctuation mark used to set off an idea within a sentence and may be used alone or in pairs. Dashes interrupt a thought in a more dramatic way than a phrase enclosed in commas, but less theatrically than parentheses.
There are actually three different types of dashes: the em-dash, the en-dash, and the 3-em dash. The em-dash can be used to replace parentheses, colons, and commas. Generally, using the em-dash makes the writing style more informal—as if you were writing to an old friend.
This is a good example of when to use such as dash in a sentence. The em dash is used to represent how the first speaker is being interrupted by the second. This makes them a useful punctuation mark when we want to convey an argument or rapid back-and-forth dialogue between characters.
The dashes' ability to create silence within the poem, forcing the reader to stop and take a break wherever one occurs, Johnson refers to as a “musical device” (x). The pause they create mimics the same effect as a comma, coaxing the reader into pausing, though on a slightly different scale.
A hyphen joins two or more words together while a dash separates words into parenthetical statements.
There are two types of dashes: em dashes and en dashes. Both get their names from their length. An em dash is about as long as the letter "m" (—), whereas an en dash is only about half that length, or the length of the letter "n" (–).
What is an end dash special character?
An en dash is a punctuation mark that is typically used to express ranges or to clarify more complex compound words. An en dash resembles a hyphen (-) but is slightly longer (–). Most keyboards don't have a key reserved for the en dash. It usually needs to be added as a special character on most writing programs.
When used appropriately—and sparingly—the em-dash is an easily implemented, powerful visual rhetoric technique for legal writing. Em-dashes typically are made by typing two hyphens between two words with no spaces between any of the characters.
A dash indicates a breaking-off of a train of thought, or an interruption in speech or thought by something else. It can also be used to indicate one or more missing letters or numbers. For example: Her final word.
Use a dash to set off an interruption that is closely relevant to the sentence but not grammatically part of it, such as a list, illustration, restatement, summary, shift in thought or tone, or dramatic point.
A hyphen joins two or more words together while a dash separates words into parenthetical statements.
A dash is used to indicate an interruption in dialogue, to introduce a list of items, or to signal an explanation the writer wants to emphasize. Ellipses and dashes are not interchangeable, but the misuse of either and both is common. A dash is a highlighter. An ellipsis takes the place of missing words.
A dash is expressed as an "em dash" ( — ) in printing, is expressed in plain text as two hyphens ( -- ) and is used in place of a comma, colon or semicolon for greater emphasis. It denotes a major break or pause and should not be overused.
We can use double dashes to denote when a side of dialogue is 'interrupted' by lines of scene description, it continues over the scene description, then is 'picked up' in the next side of dialogue. An example from the opening page of The Apartment, written by Billy Wilder and I.A.L.