I must point out before explaining my situation that I'm an English learner. However, for this question I need the help of an expert; that's why I'm asking here and not in ELL.

When writing an informal letter, I sometimes tend to use the em rule as follows:

Here I present an idea — but this is an opposite one, though. (1)

Here comes another idea — and something (closely or loosely) related. (2)

Examples of both constructions:

(1): "I hope I will overcome my father's death — it won't be easy, though."

(2): "I've found a purse — it must be Kathy's."

Is this practice correct at all? I ask because I was told it isn't: that the em rule is only used for marking dialogues (in a novel, for example).

As a side note, I've done some research indicating that em rules are used for strong interruptions: see this for instance. I suppose the provided examples fulfill this condition (if not, I'd be grateful to know why).

Thank you in advance!

  • 1
    Do you mean "em dash" rules?
    – Catija
    Jun 29, 2016 at 22:31
  • 2
    If it's an informal letter, there are no rules for dashes. Use the dashes or don't. Your call.
    – Catija
    Jun 29, 2016 at 22:32
  • 1
    @Catija Well, I used "em rule" because that's what I found as the British English equivalent for "em dash". Jun 29, 2016 at 22:34
  • 1
    So, you're saying that in BrE "rule" = "dash"? If so, then that's fine... I've never heard that but I'm American, so that's why I asked.
    – Catija
    Jun 29, 2016 at 22:36
  • 2
    Typographically, the longer em-dash—generally without any space between it and preceding or following characters—is more common in the US; in other locales, the shorter en-dash – usually surrounded by spaces – is used in identical situations. Feel free to use whichever you prefer in informal writing. Whether to use a dash is entirely a matter of personal preference and style—I myself quite like it. I do try to vary my use, however; a semicolon is a good substitute when a more formal, less breezy style is called for (and a parenthetical can convey a cozier aside).
    – 1006a
    Jun 30, 2016 at 2:37

1 Answer 1


In an informal letter, you have great deal of leeway as to what punctuation you may reasonably use. In part this is because multiple approaches to punctuation can accomplish the same thing, and in part it's because the whole point (so to speak) of punctuation is to make the sense of what you are trying to say clearer.

Let's take the two examples you bring up midway through your question:

(1) "I hope I will overcome my father's death — it won't be easy, though."

(2): "I've found a purse — it must be Kathy's."

In both sentences, what you call the em-rule serves to separate one semiautonomous idea from another—and I think it does a good job of it. But you have other options as well. For example, you might use a period in place of the em-rule:

(1) "I hope I will overcome my father's death. It won't be easy, though."

(2): "I've found a purse. It must be Kathy's."

This will give each thought maximum separation within a single paragraph. Or you can use a semicolon:

(1) "I hope I will overcome my father's death; it won't be easy, though."

(2): "I've found a purse; it must be Kathy's."

This brings the ideas closer together, with only a partial break between them. Or you could use parentheses:

(1) (1) "I hope I will overcome my father's death (it won't be easy, though)."

(2): "I've found a purse (it must be Kathy's)."

This makes the second idea seem more like an afterthought. Or you could recast the sentences slightly and use a comma in place of the em-rule:

(1) "I hope I will overcome my father's death, though it won't be easy."

(2): "I've found a purse, which must be Kathy's."

This brings the two ideas into significantly greater intimacy, as a sort of compound thought.

The punctuation you use is up to you. None of the examples above is wrong, though people may disagree about which ones are preferable and though different choices may signify different things to different people.

And finally, the notion that em-rules should be reserved exclusively for marking dialogue appears to have no authority behind it.

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