Comma Conundrums, Part 1: Rotating Sentences and the Oxford Comma

Do you remember when they told you at school that commas indicate a pause in the sentence?


(Okay – maybe it was only primary school…)

I have a piece of editing software. (Mine is ProWritingAid; other editing software is available.) I use it for a final check, and its reports regularly tell me I’ve missed out a required comma or put one in where I shouldn’t.

The explanations use phrases like subordinate clause and relative pronoun which, I confess, sail over my head when driven to get to the end of the report. When I do stop to engage my brain, I remember that a subordinate clause (sometimes called a dependent clause) is the bit that doesn’t make sense on its own, while the main clause of a sentence is grammatically complete and makes sense on its own.

When it rains, I take an umbrella.

Eventually, it sunk in that a subordinate clause that precedes the main clause of the sentence requires a comma – as in the sentence above.

But… when the sentence is the other way around, we don’t use a comma.

I take an umbrella when it rains.

That was the easy bit.cartoon swarm


Having realised I might be getting this wrong, I did some searching online and disturbed a hornets’ nest of comma counsels.

I learned that it is acceptable to dispense with certain commas where the sentence is short and meaning clear. Take, for instance this single short, clear phrase:

When it rains, I take an umbrella.

When it rains I take an umbrella.

Either version is correct. Here’s another example:

Under the spreading chestnut tree, the village smithy stands.

Here, the comma is apparently optional, but helpful due to the length of the phrase. If the subordinate phrase is longer than three or four words (depending on which website you consult) it’s better off with a comma.

Reducing the number of commas cluttering up your sentence can make for a smoother read as long as it doesn’t lead to ambiguity – cue the intervention of that thing called the Oxford comma (also termed the serial comma) to further confuse us.


The Oxford Comma

Back in those dark ages of the fifties, I was taught that the other use of commas was to separate a list of items, as in…

Bring me two apples, a pear and an orange.

The Oxford comma is the one sometimes added after the penultimate item in a list, before the and or orwhere my English teacher taught us no comma should go.

Bring me two apples, a pear, and an orange.

But why?

Sometimes it clarifies matters. Compare…

I live with Sam, a friend, and a dog.

I live with Sam, a friend and a dog.

You can see how this construction could confuse the unwary.

If there is no ambiguity to resolve, its use is a matter of style.

Editing software alerts me if I haven’t applied Oxford Commas consistently, but it picks up inconsistencies anyway – for instance, questioning uncapitalised words if they appear elsewhere with a capital letter. (Expect unwanted alerts if you’ve included a title in your report.)

Warnings about inconsistent Oxford comma-ing may be following this same consistency algorithm and safe to ignore. Advice I have found is relaxed about this but mostly agrees with Wikipedia that, ‘Inconsistent usage can seem unprofessional.’ ( )


The editing software I use can be found at don’t always agree with its alerts. Software can only apply rules (okay, algorithms); it can’t – yet – judge rhythm or style.

It also occasionally misses things. On that final sweep, I sometimes find that PWA has overlooked a rogue semicolon or a missing mandatory comma – such as the comma that should appear inside quotation marks.

Janet said, ‘I hate commas.’

‘Not as much as I do,’ said John.

Each issue highlighted by a ProWritingAid report will require human assessment, but – irrespective of the number of edits I’ve already done – its report inevitably finds errors I’ve overlooked (another reason why I decided against proofreading as a retirement career).

An online search will bring up other editing software. I have no experience of these but reviews can help you decide. Grammarly (at is well-regarded, and there is a comparison of these two resources at  

There is also a list of top ten grammar resources at with reviews of each.

commas OK

Next time…

There’s a lot of information out there about commas – too much for one blog post unless you need a cure for insomnia. In my next post, I’ll try to make sense of some more of it.

Has anyone tried other proofreading resources?

Please share your recommendations.


6 thoughts on “Comma Conundrums, Part 1: Rotating Sentences and the Oxford Comma

    1. That is a consideration, of course. ProWritingAid was free for my first year. After that, I was used to it and decided it was worth subscribing to. It sits in MS Word so I don’t have to copy-and-paste for short stories, unless I want to check a section

      Liked by 1 person

  1. Cathy, I use Grammarly and like it. It doesn’t work seamlessly with all my writing tools, and it doesn’t always agree with what I think is right. It does catch a fair amount of the detail mistakes that are so easy to miss. I don’t know that it catches inconsistent capitalization. Thanks for this great post. You’ve made a dull subject interesting. 🙂

    Liked by 1 person

    1. Glad you thought so.
      I originally started this blog when editing our writing group’s stories for print. I cringe now at some of my earlier formatting posts (how to make a simple template complicated) but I’ve lefft them all up and have updated my worst bloopers.

      Liked by 1 person

      1. I hear you, Cathy. I am the worst, and sadly when I started blogging the teacher in me thought I had this grammar thing mastered. I was so insulted when a spammer wrote that my site was “rife with errors.” I still have them, but I spend much more time proofing, reproofing and letting my husband or someone read the posts and scheduling them so I have time to read them again.

        Liked by 1 person

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