Commas, Semi-Colons, & Colons, Oh My: Part 1 – Basics

Since this is my third grammar post almost in a row – if you count my passive voice series as one post, lol – I think it’s safe to say my blog has turned into a grammar blog. This isn’t what I came here for. But I have an English degree and whoops my hand slipped and now I guess as long as my Twitter peeps have grammar questions, I’m going to be writing grammar blog posts.

ANYWAY.

Commas! Semi-colons! Colons! We’ll be talking about all three today, since all three intimidate people. They have some overlap of usage, too, so I think it’ll be clearest if I explain them as part of the same series. Today, we’ll go over the basics. In more in-depth posts in the coming weeks, I’ll explain each mark in more detail.

The main function of these three punctuation marks is to provide clarity within a sentence, although they also affect flow. As with em dashes and passive voice, there are rules surrounding the usage of commas, semi-colons, and colons – BUT you also have a certain amount of choice in the matter, depending on the situation and what you hope to achieve.

Note: I’ll be focusing on the use of these punctuation marks in prose, as poetry has a whole variety of different possible styles of punctuation. If you think you’re confused about punctuation now, go read “she being Brand” by e.e. cummings. Grab a pint of ice cream first. You’re probably going to cry.

Subnote: I adore e.e. cummings.

Commas

Commas are horribly misunderstood creatures, partly because they do so much, partly because there are disagreements over use (I will throw down over the Oxford comma), and partly because teachers tend to oversimplify things with “a comma goes wherever you pause for breath when reading a sentence aloud.”

*picks up bullhorn* COMMAS DO NOT GO WILLY-NILLY WHEREVER YOU PAUSE FOR BREATH.

Okay. Now that we’ve clarified that point, let’s talk about what commas do. Commas…

• separate the items in a list (and yes, I will be teaching Oxford comma rules here)
• join related sentences to form a compound sentence when used with a conjunction (e.g. “and”)
• offset dependent clauses at the start of the sentence
• offset clauses that interrupt the main idea of the sentence

There are more – such as separating city and state (e.g. Toledo, Ohio) – but these four lay a good foundation for comma usage.

Semi-Colons

People either adore semi-colons and use them everywhere or fear semi-colons and avoid them like COVID-19. But they’re really not that scary! Semi-colons…

• separate the items in a list for greater clarity, such as when each item already contains commas (e.g. Toledo, Ohio; Detroit, Michigan; and Albany, New York)
• join closely related sentences to form a compound sentence without a conjunction

Colons

Colons don’t seem to scare people quite as much as semi-colons but are still generally an awe-inspiring and lesser-used punctuation mark. Colons…

• separate a list from the rest of the sentence for greater clarity or emphasis
• join closely related sentences to form a compound sentence without a conjunction, particularly when the second clause explains or illustrates the first

Don’t panic if you don’t understand any of these functions! We’ll go over them in more detail beginning with the next post – with help,of course, from examples as usual.

For now, let’s get a quick first look by examining some sentences where any of these three punctuation marks could be used.

Example Sentences

First, let’s look at an example sentence involving a list.

Then they had to pack Edna’s bag with things like denture cream, an afghan she’d knitted for a competition, a photo of her son, another of his father, her prescriptions, and anything else they thought she’d want for the trip.

This version separates the items of the list with commas. However, semi-colons might make it read more easily, since it’s a longish list with some complex items (like “an afghan she’d knitted for a competition”).

Then they had to pack Edna’s bag with things like denture cream; an afghan she’d knitted for a competition; a photo of her son; another of his father; her prescriptions; and anything else they thought she’d want for the trip.

Separating the items of the list with semi-colons makes it easier to read. However, semi-colons often feel a little formal and slow down the sentence, so we might not want to use them, depending on the scene.

Then they had to pack Edna’s things: denture cream, an afghan she’d knitted for a competition, a photo of her son, another of his father, her prescriptions, and anything else they thought she’d want for the trip.

Here, a colon separates the list from the part of the sentence that introduces it. By breaking the sentence up this way, we can use commas to separate the items of the list yet maintain readability because the sentence’s opening is shorter. The list also moves along a little faster than when we used semi-colons.

Next, let’s look at two related sentences and combine them using each of our three punctuation marks.

Methodius was ready to wrap things up and get out of here. He hadn’t wanted to come in the first place.

Before I start playing with this, let me clarify: there’s nothing wrong with these sentences as they are now! We could keep that period where it is and call it a day. But these sentences will serve as a good example of how to form compound sentences using the three punctuation marks we’re focusing on today.

Methodius was ready to wrap things up and get out of here, because he hadn’t wanted to come in the first place.

To combine these sentences using a comma, we must add some sort of conjunction after the comma. Coordinating conjunctions such as “and” and “but” are common, but in this case I used the subordinating conjunction “because,” since the second sentence explains the reason for Methodius’ attitude in the first.

Methodius was ready to wrap things up and get out of here; he hadn’t wanted to come in the first place.

If the sentences are closely related – as they are in this example – a semi-colon can take the place of a period when you do not want to use a conjunction.

Methodius was ready to wrap things up and get out of here: he hadn’t wanted to come in the first place.

Colons are the clearest way to express a relationship between the two clauses of a compound sentence, since they’re generally used when the second clause illustrates or explains the first, as it does inn this example. Why is Methodius ready to leave? Because he didn’t want to come to begin with.

Again, since all three punctuation marks could be used here, your ultimate decision depends not only on the grammatical possibilities but the effect you want to achieve and the context of the sentence. Do you want it to feel more or less formal? Do you want the sentence to read faster or slower? Is the sentence equally readable with all three punctuation marks, or does one of them make it clearer and easier to read?

As always, leave any questions in the comments or hit me up on Twitter!

Read the whole series on commas, semi-colons, and colons!

• Commas, Semi-Colons, & Colons, Oh My: Part 2 – Commas
• Commas, Semi-Colons, & Colons, Oh My: Part 3 – Semi-Colons & Colons
• Commas, Semi-Colons, & Colons, Oh My: Part 4 – Breaking the Rules