There’s an excellent section in RL Trask’s The Penguin Guide to Punctuation about why we should learn to punctuate. Getting drawn into the minutiae of usage for these little marks on the page can mean we sometimes lose focus on the why. Trask says:

“When we speak English, we have all sorts of things we can use to make our meaning clear: stress, intonation, rhythm, pauses – even, if all else fails, repeating what we’ve said. When we write, however, we can’t use any of these devices, and the work that they do in speech must be almost entirely handled by punctuation.”

So, the aim is – with some notable (often deliberate) exceptions – to achieve clarity of message and to use punctuation in a consistent way to support that.

The comma splice, or spliced comma, is one of the most commonly seen errors in written English. Proofreaders and copy-editors will always have an eye out for it.

It can act as a barrier to understanding by causing ambiguity of meaning in a given sentence. It occurs when two independent clauses (these are parts of the sentence which could act alone as a whole sentence themselves) are joined by a comma only (and not by any connecting words).

The following are examples of a comma splice and are incorrect usage:

Lockdown is easing this week, I’ve booked an outside table at the pub.

I’ve finished writing my invitations, I don’t have the correct addresses for all my friends.

A dropped goal counts three points in rugby union, in rugby league it only counts one point.

A simple fix for a spliced comma might be the addition of a connecting word – and, or, while, yet or but:

Lockdown is easing this week, and I’ve booked an outside table at the pub.

I’ve finished writing my invitations, but I don’t have the correct addresses for all my friends.

A dropped goal counts three points in rugby union, while in rugby league it only counts one point.

Note that you can’t use therefore, however, thus, hence, consequently or nevertheless after a comma in this kind of sentence. There are other rules for punctuating these words.

Or you could change the punctuation mark to something which can work between two independent clauses (usually a semicolon, colon or full stop):

Lockdown is easing this week; I’ve booked an outside table at the pub.

I’ve finished writing my invitations. I don’t have the correct addresses for all my friends.

A dropped goal counts three points in rugby union; in rugby league it only counts one point.

So keep an eye out for the spliced comma – but there’s no need to nussia pilkkua, as the Finns might say.

Illustration by Lee Nixon.