Punctuation marks are a convention of written language that help readers and writers more clearly understand language in written forms. There are ten punctuation rules for using commas as punctuation marks in written American English:
- Separating items in a series
- Separating verb clauses
- After adverbials and adjuncts that precede the main clause
- Separating coordinate adjectives
- Separating nonrestrictive adjective clauses
- Separating nonessential appositives
- Separating contrasted coordinate phrases
- Separating nonessential adverbs and parentheticals
- Transitioning between quotations
- In dates, geographical places, numbers, personal titles, direct addresses, and brief interjections
The following sections explain and provide examples of the last five punctuation rules for commas in written English.
Commas With Nonessential Appositives
Use a comma to separate nonessential appositives from the rest of the sentence. An appositive is defined as a word, phrase, or clause that describes or explains another noun phrase. A nonessential appositive is defined as an appositive that is not essential to the meaning of the sentence. For example:
- An insect, a large cockroach, is crawling across the bathroom counter.
- An expert of grammatical function, Sarah Smith has graciously offered private tutoring sessions to the class.
- The crowd cheered on Espen, the fan favorite of the year.
- My mom buried my dwarf hamster, Bob, in the back flowerbed.
Do not use a comma to separate essential appositives from the rest of the sentence.
Commas Between Contrasted Coordinate Phrases
Use a comma to separate contrasted or alternative coordinate phrases. A contrasted coordinate phrase gives additional alternative information about a word, phrase, or clause. For example:
- She earned a B, not the A she was hoping for, on the midterm.
- The test should be completed in pencil, not pen.
- Some people are just ignorant, not stupid.
- My brother, not my sister, is a Rhodes Scholar.
Commas With Nonessential Adverbs and Parentheticals
Use a comma to separate nonessential adverbs and parenthetical from the rest of the sentence. A parenthetical is defined as a word, phrase, or clause that provides additional information but interrupts the main sentence. For example:
- Southern American English, for example, uses multiple modals to mitigate face threatening acts.
- The buses, however, were not cancelled in spite of the storm.
- Not surprisingly, all the students failed the quiz.
- Rodents like mice and rats, for instance, eat corn and other grains.
The use of commas with nonessential adverbs and parentheticals is related to the use of commas after adverbials and adjuncts that precede the verb clause.
Commas With Quotations
Use a comma to transition to and from a direct quotation. For example:
- "Even writers," said Sarah Vowell, "need relief from words."
- Rick Pitino said, "When you build bridges you can keep crossing them."
- "Be gentle with the young," said Juvenal.
- "I find," mused Franklin P. Adams, "that a great part of the information I have was acquired by looking up something and finding something else on the way."
Do not use a comma to transition from direct quotations that end with an exclamation mark or a question mark.
Commas with Dates, Geographical Places, Numbers, Personal Titles, Direct Addresses, and Brief Interjections
Use a comma in dates, geographical places, numbers, personal titles, direct addresses, and brief interjections. For example:
- On Monday, January 18, 1967, my parents moved to Oregon.
- My brother has lived in Chicago, Illinois, for many years.
- Our new house costs $1,333,000.00.
- Mary Queen, Associate Dean, hired the new professor.
- Espen, please pick up your toys.
- The librarian told me that, yes, one can borrow books from storage.
For more information on using commas with dates, geographical places, numbers, personal titles, direct addresses, and brief interjections, please read the article Additional Punctuation Rules for English Commas: Commas in Numbers, Dates, Places, Titles, Address, and Interjections.
Punctuation is a convention of writing that ensure clarity in written language for readers and writers. Commas perform ten basic functions in written American English, the last five of which are explained and exemplified in the above sections.
For information on the first five rules for commas in written English, please read the article Punctuation Rules for Commas in English: Using Commas as Punctuation Marks in Written American English.
Sources
"Commas." Purdue Online Writing Lab. Purdue University. 2010. Accessed 15 Mar. 2010.
Faigley, Lester. The Brief Penguin Handbook. New York: Pearson Longman. 2003.
Gibaldi, Joseph. MLA Handbook for Writers of Research Papers. 6th ed. New York: The Modern Language Association of America. 2003.
Heather Marie Kosur - About Me I earned a BA in English studies with a minor in creative writing from Illinois State University in May 2007 and an MS in ...
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