Having witnessed much uncertainty, and even helplessness, around the uses of the comma, I have decided to devote this (overdue – apologies) post to this punctuation mark. Those who have read my books will recognise the list below, but I’m sure most of you won’t have come across it, so here it is.
The comma is used:
1 To separate pre-modifying adjectives having a similar relationship with the noun being pre-modified (such commas usually translate into ‘and’):
- He now eats regular, healthy, substantial meals.
- They were locked up in a small, cold, damp, dark cell.
2 To separate short items in lists, although usually not before the last one (longer items are best separated with semi-colons):
- He bought bread, butter, cheese, eggs and coffee. (A comma before ‘and’ would be the so-called Oxford, or serial, comma. Unless it prevents genuine ambiguity, the Oxford comma is usually redundant.)
- Their march through the jungle was slow, arduous and terrifying. (Ditto)
3 To mark off extra information in non-defining (non-restrictive) relative clauses:
- Their house, which stands by the river, has been flooded. (Don’t forget to use both correlative commas – some writers do.)
- She looked at the trembling boy, whose head was bowed.
4 To mark off extra information in other non-defining (non-restrictive) modifying clauses:
- The year 1979, when he was born, was difficult for the whole family.
- Poland, where they now live, has avoided sliding into a recession.
- She gave the little girl, looking frightened, a reassuring hug.
5 To mark off non-defining (non-restrictive) amplification:
- Oily fish, such as salmon and tuna, contain important fatty acids.
- Soap operas, such as Coronation Street, are quite popular in Britain.
6 To mark off extra information in non-defining (non-restrictive) modifying phrases (apposition):
- Warsaw, my home town, was badly bombed during the war.
- We’ve just seen David, our new neighbour.
7 To mark off other included units – both phrases and clauses:
- The protest, I was convinced, had now become essential.
- All students, during many hours of testing, considerably expanded their powers of recall.
8 To mark off conjuncts = connecting adverbials (adverbials linking sentences, e.g. to begin with, secondly, likewise, furthermore, moreover, besides, in other words, consequently, therefore, however, nevertheless, until then, in those days):
- I don’t feel like going out. Besides, I have too much reading to catch up on.
- Extra information is always marked off by commas. In other words, we put commas around those details which are not essential to understanding the sentence.
9 To mark off sentence adverbials (both phrases and clauses):
- Frankly, I don’t give a damn.
- Personally speaking, the Lake District is breathtakingly beautiful.
10 To separate coordinated clauses (remove those commas and you’ll see their importance immediately):
- Teachers valued the guidance of individual officers, and inspectors found their performance satisfactory.
- He sold the premises, and the office had to relocate.
11 To mark off subordinate clauses (be that finite, as in [a] and [b]; non-finite, as in [c] and [d]; or verbless, as in [e]) preceding main clauses:
- Although they tried hard, they didn’t win.
- If you had asked me, I would have helped you.
- Having failed her repeatedly, he was unable to regain her trust.
- To be a good writer, you have to know how language works.
- When in Rome, do as the Romans do.
12 To mark off phrases in the initial position (particularly where the absence of the comma would result in ambiguity, as in [a] and [b]):
- In all, 5,000 schools were affected.
- The day after, it was dumped.
- In schools throughout the country, discontent was beginning to take hold.
13 To mark off some types of subordinate causes (disjuncts) following the main clause (although many subordinate clauses in non-initial positions are not preceded by a comma):
- His work is highly acclaimed, for it has revolutionised our thinking about the issue.
- Her poems are becoming popular, since they have struck a real chord with readers.
- I managed to meet the deadline, although it certainly wasn’t easy.
14 With direct speech (although some writers use a colon to introduce direct speech):
- Everybody shouted, “Get out now!”
- “If you give up now,” she said to them, “you’ll regret it later.”
15 When addressing living creatures (see what happens when you remove each comma):
- These are good, folk.
- Don’t blame them, guys.
- They are attacking, Ant.
- Fetch, Rex!
16 With entreaties:
- No dogs, please. (On this comma hangs the reputation of a man’s best friend.)
- Desist, I beseech you.
17 With interjections:
- Wow, that’s a lot of committees.
- Well, how about it?
Needless to say, the comma has also other uses. Important though it is, however, it often pops up in most unexpected places, in many of which it is decidedly unwelcome. But that’s the subject for another day.
I’m sorry for not having been able to standardise line spacing in this post. While some people have problems with the comma, I struggle with formatting. Oh well, we all have our cross to bear!