5 Conventions of Comma Usage (#1)
Many students have asked me questions about punctuation use in English, especially about the comma.
In general, the comma is a punctuation mark that is used within a sentence to indicate how different parts of a sentence fit together structurally.
A period (or full stop), on the other hand, is used between sentences to indicate where one sentence ends and a new sentence starts.
I decided to write up a simple summary of five common usage conventions regarding commas in English writing.
You can find #1 below. #2 – #5 will be sent to you separately in the upcoming weeks.
A note about punctuation:
Commas are a type of punctuation, and punctuation is a human invention whose purpose is to make sentences easier to understand in writing. (Writing itself is a human invention.)
Punctuation is not actually part of the natural language. That is why, when we talk about English grammar, we don’t need to take punctuation into consideration at all.
When we talk about punctuation (including commas), we are only talking about "usage conventions" in writing.
It is important to understand this because, sometimes, people follow different conventions for punctuation or deliberately avoid following certain conventions for different reasons. For example, some magazines might have a certain "house style" that differs slightly from conventional use.
The main thing to understand about punctuation convention in general is that its purpose is to make the structure of sentences easier to "break down" in writing and reading.
All the conventions that we will talk about will serve this purpose.
Conversely, if a punctuation mark makes a sentence harder to read, it is definitely not used "correctly."
Commas: usage convention #1
We usually put a comma in front of a clause linked by a coordinating conjunction.
e.g. I said "hi" to him, and he waved back at me.
e.g. I said "hi" to him, but he ignored me.
e.g. I said "hi" to him, so he turned around.
Coordinating conjunctions like "and," "but," "or," "so" connect clauses (with finite verbs) that are completely independent from each other structurally and are only connected "externally" because of a certain continuation of meaning.
We usually put a comma before this coordinating conjunction linking the separate clause – for example, before "and," "but," and "so" in the example sentences above.
We usually don’t put a comma in front of clauses linked by subordinating conjunctions like "because," "although," and "if":
e.g. He waved at me because I said "hi."
(no comma before "because")
Mini Exercise
Where should we put commas in the following sentences to reflect convention #1?
a. These drugs are in the early stages of research and it may be several years before they’re available.
b. Formulas are being touted online as an extra safeguard against the virus but they’re not approved by the government.
5 Conventions of Comma Usage (#2)
Commas: usage convention #2
We usually put a comma after a topicalized modifier.
e.g. After the competition, we went for a drink.
e.g. In the end, I said "okay."
e.g. Lying on the beach, I felt very relaxed.
The natural position for a modifier that modifies the central action of a clause (the action of the subject + finite verb) is at the end.
However, since this modifier modifies the whole clause, it can be moved around within the clause without affecting the meaning.
This modifier can be moved to the front of the clause as well.
We usually put a comma after this modifier that has been moved to the front of the clause to indicate that the subject (the actual "start" of the clause) comes after it.
e.g. We went for a drink after the competition.
(natural position of the phrase "after the competition")
e.g. After the competition, we went for a drink.
(topicalized position of the phrase "after the competition," with a comma after it)
This convention applies to embedded clauses linked by subordinating conjunctions as well:
e.g. Because I love him, I did this for him.
e.g. Although the movie was boring, he did not fall asleep.
e.g. Since they came, we have had a lot of fun.
The natural position of an embedded clause linked by a subordinating conjunction is at the end:
e.g. I did this for him because I love him.
(natural order)
This embedded clause can be moved to the front of the other clause because it modifies the whole of that other clause.
When this happens, we usually put a comma after it:
e.g. Because I love him, I did this for him.
Mini Exercise
Where should we put commas in the following sentences to reflect convention #2?
a. In the meantime some people are turning to over-the-counter nasal sprays.
b. As we approach winter virus season some people may be looking for additional protection against contracting Covid-19.
5 Conventions of Comma Usage (#3)
Commas: usage convention #3
We usually put commas in between parallel elements in a list of more than two.
e.g. I like apples, oranges, and bananas.
e.g. I like to dance, (to) sing, and (to) act.
When there are more than two parallel elements in a sentence playing the same grammatical role, we usually use commas to separate them.
Mini Exercise
Where should we put commas in the following sentences to reflect convention #3?
a. This was reported by different journalists in 2006 2008 and 2010.
b. Peter Coleman has experience working as a private chef in celebritie’s homes at five-star hotels and on luxury yachts.
5 Conventions of Comma Usage (#4)
Commas: usage convention #4
We usually put commas around (or in front of) adjectives that are “not essential” for the core intended meaning in a specific context.
e.g. The athlete collapsed to the ground, gasping for breath.
e.g. This blue dress, which I bought for $100, is my favorite.
e.g. The car, red, is very easy to spot.
Adjectives are words, phrases, or clauses that modify a noun.
In the context of a particular sentence, if an adjective is essential to the intended meaning, we usually don’t put commas around it:
e.g. The dress that I bought for $100 is my favorite.
In this sentence, the relative clause “that I bought for $100” is an “essential” adjective for “the dress” if the intended meaning is to point out this specific dress (我用$100 買的那條裙 （而非其他裙）是我最喜歡的).
The meaning would not be expressed if we take out this adjective:
e.g. The dress is my favorite. **
(not okay for the meaning of "我用$100 買的那條裙 （而非其他裙）是我最喜歡的")
When an adjective is “essential” like this, we do not put commas around it.
However, when an adjective is “not essential,” we usually put commas around it to indicate that it is “extra”:
e.g. This blue dress, which I bought for $100, is my favorite.
(The relative clause adjective “which I bought for $100” is “extra” if our core intended meaning is only "這條藍色裙是我最喜歡的".)
We can take out this “extra” adjective without affecting the core intended meaning:
e.g. This blue dress is my favorite.
When this is the case, we usually put commas around the “extra” adjective:
e.g. This blue dress, which I bought for $100, is my favorite.
An easy “test” for this type of comma:
If you can take out the adjective without affecting the core intended meaning of your sentence, it is “extra,” and we would usually put commas around it to indicate that it can be “taken out.”
e.g. The CEO, who is 65, is retiring this year.
Can “who is 65” be taken out without affecting the core meaning?
Yes, so the convention is to put commas around this relative clause.
Mini Exercise
Do we need commas in the positions indicated by ( ) according to convention #4? The intended meanings are in Chinese underneath.
a. A construction worker ( ) who makes $23 an hour ( ) would not be able to keep up with inflation.
（一個每小時賺23元的建築工人不能趕上通脹）
b. Ariel’s new job ( ) which pays $50 an hour ( ) is much more stable than her old one.
（Ariel $50的新工作比她舊工作穩定。這新工的時薪是$50。）
5 Conventions of Comma Usage (#5)
Commas: Usage convention #5
We can put commas in "structurally sensible" positions to break up a long sentence.
e.g. We think that it is important for us to help them achieve this goal, and for us to do so as soon as possible.
Generally, we can use commas to break up different parts of long sentences so that they are easier for the reader to read.
These commas create "pauses" for readers.
However, we would still only "pause" in "sensible" places – that is, places that would reflect the overall structure of the sentence rather than in random places.
For example, in the example above, the comma before "and" is not a conventional use since this "and" is not linking a separate clause.
There are also just two parallel elements, "for us to help…" and "for us to do…," which normally do not require a comma as separation.
(As in, this comma use fits neither convention #1 nor convention #3)
However, this comma is still quite natural here because it is breaking up a long sentence in a position that is "sensible" – between the two parallel elements.
Mini Exercise
Are the places marked by ( ) "sensible" positions for a comma according to convention #5?
a. Some parents would sleep on sofas or chairs to vacate the family’s only bed with proper bedding and support for their young children (,) while other families would have children sleeping on mattresses or blankets on the floor so that the working adults can have a good night’s sleep.
b. It makes me so angry and upset that somebody would do such a thing to something that has been so special to so many people over so many generations (,) just in order to take a video for social media.
Summary Exercise
We have now looked at five of the most common usage conventions for commas. Remember that all of these conventions apply to sentences all at the same time! Read the following paragraph and think about which usage convention each of the commas reflects:
The tree was made famous globally by the Robin Hood movie, but for local people, it was much more than that. It was a place for engagements, weddings or spreading ashes, or just somewhere to go for some peace and tranquillity. A woman, who said generations of her family had visited the tree, was sobbing, with her head in her hands.
Adapted from Jenny Gross. (2023, Sept. 28). ‘Beloved Tree in England Is Felled in "Act of Vandalism"’. The New York Timeshttps://www.nytimes.com/2023/09/28/world/europe/sycamore-gap-tree-uk.html