Some of comma commentary is pretty straightforward. But there are a few grey areas, mainly around the Oxford comma, comma splices and separating adjectives.

Use commas where you’d pause, if you said it out loud

Like in lists, or introducing something as an aside: ‘George Orwell, the writer, once said...’

Oxford comma: Use it when you need it

This is the one in bold here, after ‘Rebecca’ and before ‘and’: George, Jess, Rebecca, and Fran are on the tennis squad. (It’s also called the serial comma, Harvard comma, and series comma.)

It’s also the one that people fight over the most: people are often firmly in one camp or the other. We say: just use it where it helps you be clearer. Otherwise, don’t worry about it (use it or don't).

If an item in your list has an ‘and’ in it then you’ll need to use an Oxford comma so no one gets confused. Like this:

There are loads of good places for lunch near the office. But a lot of the time it’s a choice between Pret a Manger, Tas, and Konditor and Cook.

Without the comma before the ‘and’ people might think there’s one sandwich shop called ‘Tas and Konditor’ and another one called ‘Cook’.

Commas splices

A comma splice is where you use a comma to separate two independent clauses, when you should actually be using a semicolon, a dash or a conjunction (like ‘and’, ‘but’ or ‘so’). It’s wrong (to be blunt). Because commas are used for separating, not connecting.

Spliced: Jude loves to travel, she goes on holiday whenever she can.

Each clause has a subject and a predicate and forms a complete thought – so it could stand on its own as a sentence. That means a comma doesn’t work.

Not spliced: Jude loves to travel; she goes away whenever she can.

Or: Jude loves to travel so she goes away whenever she can.

Or: Jude loves to travel – she goes away whenever she can.

If you read it out loud you should be able to hear it.

The exceptions

As is the unofficial theme of this guide, there’s always an exception. Famous comma splices include I came, I saw, I conquered which comes courtesy of Caesar (this is also an example of a poetic device called asyndeton), and this one from W Somerset Maugham in Of Human Bondage: ...often he sat and looked at the branches of a tree silhouetted against the sky, it was like a Japanese print...

So splices are sometimes alright when the clauses are short and similar, or as a poetic device. Or maybe Lynne Truss is right when she says: ‘so many highly respected writers observe the comma splice that a rather unfair rule emerges on this one: only do it if you’re famous.’

Separating a list of adjectives

Ever wondered where to put the comma in a list of adjectives? Well, it depends on the type of adjective.

Coordinate adjectives

Describe the noun but each adjective is doing its own bit of describing, for example, ‘a long, wordy email’. The email is both ‘long’ and ‘wordy’.

Cumulative adjectives

Don’t separately describe the noun. The adjective directly before the noun pairs with it, and then the adjective before that describes the pair. For example, ‘our most experienced in-house trainer’. The person we’re discussing is an ‘in-house trainer’. And they are the most ‘experienced’.

So how do you know if your adjectives are cumulative or coordinate?

Well, you can rearrange coordinate adjectives (‘a wordy, long email’) and stick an ‘and’ between them (‘a long and wordy email’). But you can’t do either to cumulative ones. An in-house experienced trainer? No way.

So if your adjectives pass the rearranging or ‘and’ test, then you know you’ll need to separate them with commas.

Spot the difference

This is an interesting, concrete example. (Coordinate. You might write this in some feedback.)

This is an interesting concrete example. (Cumulative. You’re more likely to hear this on a building site. Or at the Barbican.)

*But, be warned. For native English speakers, it will feel very odd to rearrange certain coordinate adjectives. ‘Red, big lorry.’ You see? This is because of a little-known, but universally adhered-to, rule about the hierarchy of adjectives. In English, we use adjectives in the following order:

opinion / size / age / shape / colour / origin / material / purpose – NOUN.

So: ‘Beautiful, big, old, round, silver, French, metal mixing bowl’. Any other order sounds wrong.

‘Big, old, beautiful, French, silver, round, metal mixing bowl?’

‘Round, old, silver, big, beautiful, metal, French mixing bowl?’

‘My Greek, Fat, Big Wedding?’

(Just be grateful if you do this subconsciously, and didn’t have to learn the rule in an English language class.)