Dot and Comma Symbol: What Each One Is and How to Use Them
Learn what the dot and comma symbol each means in English punctuation, how they differ in function, and how screen readers handle them in digital text.
I've been working on a book about punctuation, which is why I'm writing this article. The comma and the dot are two of the most common punctuation marks in English, but they're often misunderstood.
The dot symbol is the period, a small dot placed at the end of a sentence. It signals that the sentence is complete, or that you should stop reading for a moment. In other words, it's one of the sentence-ending punctuation marks (the others being the question mark and the exclamation point). When you write an English sentence, it ends with a dot.
The comma symbol is a small curved mark used within sentences. Its main purpose is to insert a pause. For example, when you join two independent clauses with a conjunction, you use a comma before the conjunction:
He likes to eat fruits, cake, vegetables, and pasta.
When you want to set off introductory phrases, you can use a comma:
The criminal, said the judge, was an idiot.
You can also use commas to separate items in a list:
He likes to eat fruits, cake, vegetables, and pasta.
Or to mark interjections:
Hey! He likes to eat fruits, cake, vegetables, and pasta.
In short, the dot is used to signal that a sentence is over, while the comma is used to signal that there’s a pause inside a sentence.
How the Two Symbols Differ
The two symbols serve very different purposes, so their positions in a sentence are very different. The dot is always at the end of a sentence, while the comma is always somewhere in the middle. But even though they serve such different purposes, the two symbols are not both categorized as “sentence-ending” punctuation marks. In fact, along with the colon and the semicolon, the comma is grouped with marks indicating how written text should be read and understood.
This is not to say that all uses of the comma are wrong — just that many people misuse it. In fact, the comma is the most commonly used and misused punctuation mark in English. The most common mistake is the comma splice, where you join two independent clauses with a comma instead of a conjunction:
He likes to eat fruits, cake, vegetables, and pasta.
Joining unrelated or already-long sentences with a comma burdens the reader, because it makes it harder to tell where one sentence ends and another begins.
How Screen Readers Handle Them
Screen readers, the software programs that help blind people read digital text, handle the dot and comma differently. Most screen readers will announce the dot when it appears in text. However, they usually don’t announce the comma, since it’s a much more subtle marker than the dot. For example, if you have a sentence like:
He likes to eat fruits, cake, vegetables, and pasta.
A screen reader might just pause after the word “fruits,” without saying anything about the comma. If you type the word “don’t” into a document, a screen reader will say “don’t,” not “don apostrophe t.” So screen readers do not reliably announce every single comma, period, and apostrophe in your text.
Some screen readers may announce the dot when it appears in text. However, the way they handle the dot isn’t consistent across products. Some screen readers may announce the dot only when it appears at the end of a sentence, while others may announce it every time it appears. And no single screen reader product handles the full set of punctuation marks correctly.
Manufacturers decided that most users don’t need to hear every comma, period, and apostrophe. This decision was partly by design.