You’ve spent months in your new position carefully noting the boss’s little style bugbears. That important brief has bounced up and down stairs a few times. The end is in sight, and you’re quite proud of it.

But unexpectedly it bounces one more time. You forgot the comma after ‘however’. Sigh. And by the time you get it back upstairs, the approver will be at back-to-back meetings for the next two days.

Ah, the comma! The smallest, commonest, trickiest punctuation mark. Too many rules! Please, sir, my brain is full.

All is not lost. There’s no magic bullet here – some things really do take time and practice to master – but there are a few good tips. Let’s focus on one of them: read it out loud. If there’s a natural pause in speech, there will usually be a comma in writing (unless of course there’s something heavier, like a semicolon, colon or full stop).

I stress: if there’s a natural pause in speech, there will usually but not always be a comma in writing. Commas are tricky because they have two uses: they originated to mark natural pauses for people reading out loud; but nowadays they’re also used to point out the grammatical units of a sentence, and that may not always correspond to spoken pauses.

The result of this mixed use is that today some natural pauses don’t earn a comma, and some pauseless places in a sentence do. You expected a simple rule? Sorry.

However, one area of commadom where ‘mark the natural spoken pauses’ does work reasonably well concerns what modern grammarians call ‘supplements’. That’s an umbrella term for a variety of elements that are not integrated into a clause – if you leave them out, the sentence is still grammatical and the core meaning is still the same. They have various traditional names:

• Nouns or noun phrases in apposition: ‘The key stakeholders, companies in the industry, have new concerns.’
• Participial phrases: ‘The key stakeholders, given the findings of the trial, have new concerns.’
• Non-defining relative clauses: ‘The key stakeholders, who are companies in the industry, have new concerns.’
• ‘Sentence adverbs’ – an adverb that expresses the speaker’s attitude to the whole situation, rather than modifying a verb: ‘The key stakeholders, not unreasonably, have new concerns.’
• ‘Conjunctive adverbs’ – a joining adverb or similar expression that expresses the logical relation between sentences in some way (however, therefore, nevertheless, moreover, thus, for example, in addition …): ‘The key stakeholders have new concerns. However, they are amenable to further negotiation.’

Elements like these are set off by two commas if they’re in the middle of a sentence. Yes, two – it’s really uncool to write ‘The key stakeholders, companies in the industry have new concerns.’ Or one comma at the beginning or end of a sentence. The pauses in speech are usually a good guide.

It’s important to get this right because sometimes the commas are needed to make the meaning clear. Compare:

‘The key stakeholders, who are companies in the industry, have new concerns.’ (The key stakeholders are companies in the industry. They have new concerns.)

‘The key stakeholders who are companies in the industry have new concerns.’ (There are other key stakeholders who are not companies in the industry. By implication they don’t have new concerns, although that is not clearly stated.)

A similar ambiguity can happen, though less commonly, with ‘however’:

‘The results are of concern; however, the margin of uncertainty is significant.’

‘The results are of concern however significant the margin of uncertainty is.’

So your boss was right to be picky about the punctuation of ‘however’.

There’s more about commas in the new Australian Government Style Manual.