Hyphens group concepts clearly to help readers to understand a sentence the first time they read it.
Here are four how-to tricks with hyphens.
Hyphens help create distinct conceptual units. They show that the two or three words in front of a noun are creating a single concept that describes the noun.
If I write well known singer, it could be read two ways: do I mean a healthy, known singer, or a singer who is well known? To be clear that I’m not talking about the singer’s exercise regime, I hyphenate: well-known singer.
If I write two week old chicks, do I mean two chicks that are a week old (two week-old chicks), or chicks that are two weeks old (two-week-old chicks)? Hyphens make my meaning clear.
If I write three metre long poles, I use hyphens to show whether I mean three poles, each of which is a metre long (three metre-long poles), or a series of three-metre-long poles.
You may use a hyphenated phrase in one sentence, and not use it in the next sentence. Why? No one will get confused if the noun comes first, so no hyphens are necessary when it does.
The singer is well known.
The chicks are two days old.
The poles are three metres long.
Another little trick: don’t hyphenate if one of the words ends in –ly. Why? No one will get confused about what goes with what, so no hyphens are necessary.
a badly needed improvement
a quickly answered email
Hyphens help us pronounce a prefix in front of a word that starts with a vowel.
co-opt — prevents us saying ‘cooopt’
pre-empt — prevents us saying ‘preeempt’
de-ice — prevents us saying ‘deyce’
Hyphenate fractions and numbers from 21 to 99.
Some words grow together over time. They start off as two separate words, then they become hyphenated, and finally they grow into one word.
Use a hyphen when a word is at the middle stage of growing together. Look in an online dictionary to find out what stage a word is up to. According to oxforddictionaries.com, ‘decision-making’ is in the middle of the process — we currently hyphenate it.