Are these uses of em dashes extant in English-language fiction?

Question

I'm giving some authoring advice to a newer writer. She has a curious convention where she uses an em dash at the end of a sentence in the narrative when she wants to indicate an abrupt change of subject (call this "case 1"). Her writing is private, hence the following is an example I've contrived:

"I think that's great," said Billy.
Frank nodded his approval. Jill was of a mind to object.—
The bookshelf behind the three children collapsed with a mighty crash.

A second convention (case 2) is that she uses an em dash in dialogue, at the end of a sentence (and often in place of a period), to indicate that a character is interrupted or otherwise intended to say more. E.g.,

"They should really build better bookshelves," Jill said.
"Yeah," Billy agreed. "And better beds. And better cabinets. And better cars—"
"And better everything," Frank cut him off.
"No. Not better everything! —"
"Whatever. It's not important."

Note that in case 2, I'm not referring to the widespread convention of using an em dash as a terminator for an incomplete sentence. Case 2 does not comprise, e.g.:

"Do you think we should clean up the—"
But Jill froze as she saw the expression on Billy's face.

None of the writing guides I've consulted on the use of em dashes suggest that either case 1 or case 2 are valid uses. However, I was also surprised to find that most don't include the "terminate an interrupted or incomplete sentence" case either, and I've seen it used in hundreds of books.

My inclination is to tell this author that her conventions are flat-out wrong and that she ought to remove the em dashes, but I wanted to check with the online community first.

Am I just out-of-date? Is either of these uses of an em dash something that can be found in English-language fiction today? Are there any examples that are publicly accessible online?

Answer 1

The em dash is sometimes used to signal interrupted dialogue. Interruptions can occur due to events or other dialogue, sometimes after a complete sentence and sometimes not. For instance, in Shakespeare's Titus Andronicus, Act I, scene i (Folger Library), line 377ff, Marcus and his two sons interrupt each other as they plead to Titus:

MARCUS
Brother, for in that name doth nature plead—

MARTIUS
Father, and in that name doth nature speak—

TITUS
Speak thou no more, if all the rest will speed.

MARCUS
Renownèd Titus, more than half my soul—

LUCIUS
Dear father, soul and substance of us all—

MARCUS
Suffer thy brother Marcus to inter / His noble nephew here in virtue’s nest [...]

Then in Toni Morrison's novel Beloved (p. 22), the em dash indicates an interruption in dialogue:

"It's the house. People don't—"

"It's not! It's not the house. It's us! And it's you!"

The convention also appears in Patricia Powell's novel The Padoga (p. 210), now ending a complete sentence:

"But, Dulcie. I mean, you friends all these years. You family for each other all these years. Maybe I interfere in things that don't concern me, but is my fault, it was—"

"Is better that way, Mr. Lowe." [note: the character commonly starts sentences with "is."]

The dialogue in The Pagoda is a counterexample to the idea that the em dash can only close out an incomplete sentence. If there is a pattern here, it isn't oriented around sentences or other syntactic units, but rather whether the speaker would have continued the dialogue. Chicago Manual of Style (17th edition) 6.87 hints at this in its wording:

An em dash or a pair of em dashes may indicate a sudden break in thought or sentence structure or an interruption in dialogue.

There are three instances here: (a) a sudden break in thought, (b) a sudden break in sentence structure, and (c) an interruption in dialogue. Within those guidelines, a break at the end of a complete sentence would be (a) if you consider multiple sentences part of the same train of thought or (c) if you think of the dialogue as possibly continuing for more sentences.

However, I can't recall an em dash being used according to your first case in modern publishing. That may occasionally appear in old writing, where em dashes after commas and semicolons are more common. The common editing choice, again supported by Chicago (6.89), would be to only use an em dash after a period if the period marked an abbreviation:

No one—at least not before 11:42 p.m.—could have predicted the outcome.

Answer 2

The first use you list looks maybe like an attempt at a section break. (It could also just be that your author is using nonstandard punctuation here.) In print novels section breaks are often fancy (e.g. asterisms), but on the web, they're often represented as horizontal rules, which in some formatting software (e.g. markdown) are typed as a series of hyphens on its own line. See this:

---

The second quote you gave has two em dashes. The first looks pretty standard, but the second looks odd because it comes after a punctuation mark when em dashes almost always replace it. And when they don't (since sometimes not removing a "?" is needed for clarity), the dash comes before the punctuation.

Wikipedia gives a fairly comprehensive list of uses for the em dash, including in dialogue. There are some more unusual uses listed but they don't seem to apply here.

Answer 3

Kurt Vonnegut comes to mind as a modern writer who endorsed this use of em dashes. He recommended them over ellipses, which have become more common for this, but were originally supposed to mean that you’re leaving a few words out.

Emily Dickinson, though, has to be the writer most famous for using em dashes as pauses.

Answer 4

A long while ago an em-dash at the end of a line indicated an interruption or trailing-off of speech. That is now quaint.

Some writers use an em-dash in speech to indicate a hesitation. A really practical way is to think of it as having the role of a comma in plain text. For example "I don't know how to say this -- but ..." I use this and find it very handy, however there's a slippery slope between em-dash, period and ellipsis. Remember that people don't talk using precise grammar, and in real life they er and um a lot while also starting to say something without quite knowing how to continue. Using the em-dash this way gives some flavour of this speech pattern.

From my own writing experience (30 novels) I've sometimes had very interruptive characters or situations. Not A follows B quickly but crashes into their speech. For that I use a trupt which is a slash (in the place an old book would use a em-dash) then another on the start of the next line. For example

Fred looked at me and said "Don't worry I've been driving trucks for twenty"/
/"Look out!"

You can also use this for self interruption Fred said "I've never had an accident in twenty years driv/ /Strewth!"

I suggest you have your reader look at some books and get them to tell you why they're 'defective'.