I’m willing to bet most people are happy with using full stops, exclamation marks and question marks. I’d also hazard a guess that commas don’t cause too much confusion in general (although I may return to these at a later date). And parentheses? No problem.
But what about those other ones – the ones that are a little more tricky? I’m thinking first of all about the colon and semicolon, which often seem to be used interchangeably (and incorrectly). Let’s take a closer look.
The semicolon (;)
Let’s start with the good old semicolon.
New Hart’s Rules (NHR) has a good rule for remembering when to use the semicolon, seeing it almost as a light full stop:
The semicolon marks a separation that is stronger than a comma but less strong than a full point. It divides two main clauses that are closely related and complement or parallel each other, and that could stand as sentences in their own right [my emphasis].
The semicolon can be used to break up lists where commas are used within single elements of the list, to aid readers’ understanding of the text. For example:
Yesterday I went to visit my mother, who is recovering from an operation; walked my neighbour’s dog, as he is away on holiday; and went to the sports centre to do an exercise class, swim, and catch up with an old friend.
This doesn’t just apply to lists written as sentences – it is also useful in bulleted lists, as I was reminded when attending the Plain English Campaign’s training on writing for websites:
Before going on holiday, I need to:
pack my suitcase;
take the cat to the cattery;
use up any perishable food in the fridge; and
give the spare key to the neighbours so they can water the plants.
NHR also suggests using it in place of a full stop if the sentence immediately following begins with a symbol, describing it as ‘confusing and unattractive’ to begin a sentence in this way:
Let us assume that a is the crude death rate and b life expectancy at birth; a will signal a rise in…
The colon (:)
To begin with, here’s a list summarising the point (or points, perhaps?) of the colon. This punctuation mark should be used:
- to introduce a list, bulleted or otherwise (see what I did there?);
- as a ‘follow-on’;
- after the title of a work; or
- to introduce direct speech.
Please note that in British English the colon isn’t followed by a capital letter, unless the word immediately following is a proper noun (although in US English it is). This makes sense in light of the point below about the second clause not needing to be a complete sentence.
1. Lists: The colon isn’t necessary in a sentence which contains a list if it’s already a complete sentence in itself. NHR gives the following example:
Other Victorian authors worth studying include Thackeray, Trollope and Dickens.
You could, however, restructure this sentence and use a colon instead:
There are other Victorian authors worth studying: Thackeray, Trollope and Dickens.
2. Follow-ons: This is probably the time you see colons used the most. Unlike the semicolon, the colon doesn’t need to be followed by a phrase that could stand as a sentence in its own right. Instead, it’s used as a ‘follow-on’, i.e. to precede something that follows on logically – cause and effect, premise and conclusion, statement and example(s).
NHR advises thinking of it like this: if you can precede the phrase in question with a word like therefore, namely or for example, a colon would be just as valid.
The book also notes that you can insert a dash in place of a colon with this type of usage, but this is normally better if saved for more informal contexts.
3. Titles and subtitles of works: Many works, particularly more academic titles, have a title and a subtitle. The colon is used to separate these, with house style determining whether the subtitle should begin with a capital letter or not.
4. Introducing direct speech: Although it’s more usual to see direct speech immediately preceded by a comma, it’s perfectly valid to use a colon instead. NHR says that a colon is ‘typically used to introduce more formal speech or speeches of more than one sentence, to give emphasis to the quoted matter, or to clarify the sentence structure after a clause in parentheses.’
NHR notes that you can also use a dash in place of a colon in example
Alternatives to the colon and semicolon?
Back in 2013, the College Humor website ran an article entitled ‘8 New and Necessary Punctuation Marks’. If you read this whole blog post, you’ll never need to think about using the hemi-semi-demi colon.