My friend KV suggested that I discuss em dashes. Great topic! Let me discuss hyphens first on our way to understanding em dashes.
The word hyphen comes from late Latin and Greek: huphen ‘together’ and from hupo ‘under’ + hen ‘one.’ From this origin, the function of a hyphen emerges: it connects words and makes these words one term.
The hyphen is that (-) sign typically next to the 0 key. It is shorter and stubbier than an en dash (–) and an em dash (—).
Consider the length of these signs:
- hyphen –
- en dash –
- em dash —
Let me share with you one use of a hyphen.
1. Use a hyphen to connect word elements and make these into one adjective term that comes before a noun.
Let’s consider the sentence: I am nervous about interviews made on the spot.
The phrase on the spot describes interviews–it is an adjective phrase placed after the noun it describes. If we put this phrase before the noun interviews, we will have this sentence: I am nervous about on the spot interviews.
Without hyphens, the resulting sentence is hard to read. Its meaning is not immediately accessible. What we can do is insert hyphens in the phrase that describes the noun interviews–that way, the reader immediately realizes that all three words on the spot describes interviews. Our new sentence: I am nervous about on-the-spot interviews. Easier to read, right?
We do the same for this sentence: Tony’s son, who is six years old, won the lottery.
The phrase six years old describes the son. If we transfer the phrase six years old and place it before the word son, we have this: Tony’s six year old son won the lottery.
When we first read the resulting sentence, we might be led to think that Tony has six children. To create easier reading, we insert the hyphens between the words that go together: Tony’s six-year-old son won the lottery.
Note that we dropped the s in years when the word becomes part of a compound modifier (an adjective that has more than one word). Dropping the s makes it easier to read the sentence aloud.
The hyphen helps establish meaning. Consider this sentence: Martha is considering solutions for the short term and the long term.
What if we place the phrase for the short term and the long term before the word solutions, like this: Martha is considering short and long term solutions.
What is Martha considering? Is she considering term solutions that are short and long?
What if we add one hyphen: Martha is considering short and long-term solutions. What is Martha considering now? Two things: short solutions and long-term solutions. Without the hyphen after the word short that links it to term, then the “short solutions” has no reference to time. This sentence is not faithful to the meaning of the original sentence. We should insert the hyphen after short, thus: Martha is considering short- and long-term solutions. (This is called a suspensive hyphen: a hyphen that is placed next to only one word.)
The hyphen creates easier reading. Try reading this sentence quickly: After sales services, warranty coverage and manpower training are also included in this bid.
Did you stumble while reading it? I did. I thought at first that the preposition after is part of an introductory phrase. It turns out that after sales service is one of three subjects in this sentence: after sales service, warranty coverage, and manpower training.
How do make the reading easier? We insert a hyphen in the phrase after sales which describes the noun services--this refers to services given after a sale has been made. We write: After-sales services, warranty coverage, and manpower training are also included in this bid.
(Aside: I’m a fan of the serial comma–also called the Oxford comma–so I placed a comma before and.)
If you need a hyphen overload, let’s consider another sentence: After having addressed issues of structural feasibility in the earthquake and typhoon prone tropics, the partners’ concern in finding an architect took a more circuitous route.
The underlined portion refers to the tropics that are “prone to earthquake and typhoons.” If we–as the sentence above did–transfer this phrase before the noun tropics, we have to hyphenate the phrase, thus:
After having addressed issues of structural feasibility in the earthquake- and typhoon-prone tropics, the partners’ concern in finding an architect took a more circuitous route.
Note that the word earthquake also needs its own hyphen so it can establish a relationship with the word prone. The hyphenated term earthquake-prone is an adjective describing tropics. Without such hyphen, the word earthquake is just a noun.
In the same vein, the phrase “a corporation owned and controlled by the government” can be rewritten as “a government-owned and -controlled corporation.” Again, notice the hyphen before the word controlled. The hyphen is necessary to mark the relationship of the word controlled with government.