Writers whose first language is not English tend to omit commas in places that need commas. This is the most common type of punctuation errors among non-native English speakers.
The most common uses of commas are as follows:
- Between two full sentences linked with a conjunction
- Around an appositive
- Around a parenthetical or nonrestrictive phrase
- After an if clause in a conditional sentence
- In serial lists
- After introductory words or phrases
- Around a direct address
- Before a tag question
- Between multiple adjectives
Between two full sentences linked with a conjunction
Typically, when you have two full sentences linked by a conjunction, you should put a comma before the conjunction. For example: I wish the best for you, and I will also try my best at my new job. The two full sentences in this case are: 1) I wish the best for you. and 2) I will also try my best at my new job. Some argue that when the two sentences are closely related to each other in meaning, a comma is not necessary. Take this example: Larry vacuumed the house and his sister did the laundry. However, judging if two sentences are closely related is a subjective measure that is bound to have split opinions. Some may find that the two sentences in the prior example are not closely related enough to omit the comma. Because this is such a subjective matter, when in doubt, always put a comma when there are two full sentences linked with a conjunction.
Around an appositive
An appositive is a noun or phrase that describes another noun. The words a writer in the following sentence is an appositive that describes Bob: Bob, a writer, has been working on a novel for two years now. When the appositive introduces essential information to the sentence, however, it is better to omit the surrounding commas as such: Bob’s new novel, Up in the Sky, **is now a New York Times Best Seller. → Bob’s new novel Up in the Sky is now a New York Times Best Seller.
Around a parenthetical or nonrestrictive phrase
Similar to appositives, commas are to surround a parenthetical or nonrestrictive phrase unless the information is essential to the sentence. In the following two examples, the parenthetical and nonrestrictive phrases, respectively, are non-essential parts of the sentence, and therefore are surrounded by commas.
- Example 1: The new project, unfortunately, will be led by the irresponsible Jason.
- Example 2: The investment firm, which is led by India’s top investment bankers, is famous internationally.
The easiest way to see if you need commas or not is by removing the phrase from the sentence and seeing whether the main information can still be conveyed. If so, then you would need commas around your parenthetical or nonrestrictive phrase.
After an if clause in a conditional sentence
Conditional sentences always have a comma following the if clause. Take this sentence: If you do not cooperate, the project will fall apart. Non-native English writers often forget to add a comma after an if clause. If you have trouble knowing where the if clause ends, see where the word then would fit into the sentence like so: If you do not cooperate, then the project will fall apart. The comma will typically precede the spot where then would go. Then is not necessary to have in every conditional sentence, but when figuring out where the if clause ends, adding then can help immensely.
In serial lists
Another common use of commas is in serial lists: Jesse went to the store and bought apples, bananas, and oranges. In a list of three or more objects, there should be a comma after every object except the last in American English. In British English, you would omit the last comma before the conjunction as such:
- Jesse went to the store and bought apples, bananas and oranges.
After introductory words or phrases
Introductory words or phrases open sentences, supplementing them with additional information, and can often be taken out without affecting the grammar of the rest of the sentence. When an introductory phrase is short (typically three words or less), the comma after it is optional. Short, however, is subjective and often subject to dispute, so when in doubt, it is safe to put a comma after all introductory words or phrases: After that, Lexi took the subway home. Longer introductory phrases, of course, always are followed by a comma without question: While he chewed on a piece of hay, Jay strolled down the path like he had nothing better to do.
Around a direct address
When calling someone by their name, nickname, or title, the word should be enclosed by (a) comma(s) like in these examples:
- Example 1: John, could you hand me the list of vendors?
- Example 2: Where are you going, Mom?
- Example 3: I will ask you again, sir, if you were drinking under the influence.
You would not use commas, however, when you are using the name or title as the subject or object of the sentence:
- Example 4: Mrs. Smith asked us to turn in our homework in the morning.
- Example 5: Please report your findings to Attorney Johnson.
Before a tag question
Without exception, every tag question should be preceded by a comma. A tag is a short question that comes at the end of a statement to confirm the information in the sentence as such:
- Example 1: You went to the party without telling Mom, right?
- Example 2: That survey took forever to fill out, didn’t it?
A quick way to see if you have a tag question is by taking out the words you think compose the tag question, and if what remains is a full sentence on its own, then you probably have a tag question at the end: You went to the party without telling Mom. (right?)
Between multiple adjectives
When you have more than one adjective of a similar category, you separate the adjectives with (a) comma(s). The generally accepted order of the categories of multiple adjective is as follows: opinion, size, physical quality, shape, age, color, origin, material, type, and purpose.
- Example 1: The clever, calculative salesman found unique ways of increasing his commission.
- Clever and calculative are both opinion-based adjectives, so a comma would be necessary between them.
- This would not work the same if the adjectives are of different categories:
- Example 2: The large, wooden frame fell down during the thunderstorm. → The large wooden frame fell down during the thunderstorm.
- Large and wood are size and material adjectives respectively, so they are not part of the same adjective category and do not a comma between them.
You can also try changing the order of the adjectives to see if it gives you a clearer picture of whether your adjectives are of the same category.
Although commas may seem like a nonessential part of English to non-native speakers, correct use of punctuations such as commas differentiates you from other international writers, as commas give necessary pauses in the needed spots.
Check out Engram, which works as a punctuation checker, to see if your sentences are missing any necessary commas.