Commas are the workhorses of a sentence: they corral words into recognizable units that can be understood by the reader. When language was primarily spoken, pauses and inflections signaled to the listener these word groupings and consequently the speaker’s meaning. Today, much communication is written; we rely heavily on punctuation, often commas, to group our words into content the reader can easily grasp. There’s a big difference between the meaning of “Let’s eat Grandma!” and “Let’s eat, Grandma!,” and the humble comma is what makes the difference between a call to dinner and cannibalism. E.g., Steven Pinker, The Sense of Style 284 (2014).
Notwithstanding the crucial role of commas in sentence clarity, commas can be controversial. Some writers like to sprinkle them throughout their prose while others prefer to use them sparingly. Harold Ross, the editor of The New Yorker during the 1930s and 1940s, and the humorist James Thurber famously quarreled over commas. Ross favored their frequent use, while Thurber disdained them. Thurber recalled that Ross described the American flag as the “red, white, and blue,” whereas Thurber’s preference was the “red white and blue.” Thurber explained, “[A]ll of those commas make the flag seem rained on. They give it a furled look.” Quoted in Lynne Truss, Eats, Shoots & Leaves 68–69 (2003).
Thurber concentrated on style, but we lawyers focus more on clarity and on using the punctuation conventions that are recognized by literate writers. Today, the trend is to use fewer commas, but some rules remain. Pinker, supra, at 284–85. Let’s focus on several conventions that mandate the use of commas in sentence structures.
1. Always Use a Comma When Joining Two Independent Main Clauses with a Conjunction. What’s an independent clause? It’s a clause containing a subject and a verb that can stand alone as a sentence: The cowboy took off his white hat. When a writer adds another independent clause of equal importance to provide the full picture and uses the conjunction and, but, for, or, nor, yet, or so, the writer must use a comma before the conjunction: The cowboy took off his white hat and waved it, but the cattle were not impressed. William Strunk Jr. & E.B. White, The Elements of Style 5 (4th ed. 2000); Bryan A. Garner, The Redbook: A Manual on Legal Style§ 1.4 (3d ed. 2013).
What happens when the comma is omitted? The writer is viewed as a dolt, and his or her discriminating readers mutter, “A run-on sentence! Horrors!”
What happens if the comma remains, but the conjunction but is omitted? Again, the writer is viewed as a dolt, and his or her readers mutter, “A comma splice! Horrors!” In this second example, a semicolon placed between the independent clauses in lieu of the comma and conjunction would have saved the day: The cowboy took off his white hat; the cattle were not impressed. Strunk & White, supra, at 5–6; Garner, supra, § 1.4.
A writer must use a semicolon rather than a comma when the two independent clauses are joined by a conjunctive adverb or transitional expression like however, nevertheless, accordingly, besides, then, therefore, thus, moreover, further, in general, or on the other hand. For example: The cowboy took off his white hat and waved it; however, the cattle were not impressed. Strunk & White, supra, at 6; Garner, supra, § 1.17. But the comma is still needed—it follows the adverb. Id.
2. Use Commas in Lists. The accepted punctuation rules dictate that a comma can be used to separate a series of three or more words or phrases: The cattle snickered, snorted, and laughed at the cowboy. Strunk & White, supra, at 2; Garner, supra, § 1.3. Thurber may question whether commas are needed in this sentence at all, but we lawyers recognize that, to avoid ambiguity, the writer must use commas to separate listed items. The only dispute, and it’s a heated one, is whether a comma, known as a serial or Oxford comma, should be inserted between the last two items in the list, preceding the conjunction. See Brian A. Garner, A Dictionary of Modern Legal Usage 714 (2d ed. 1995).
Many British publishers and American newspapers do not favor the serial comma. See Pinker, supra, at 293 (also citing Crosby, Stills and Nash). But most grammar and usage mavens recommend the use of that final serial comma to avoid ambiguity. E.g., Strunk & White, supra, at 2. Bryan Garner writes that the question whether to include the serial comma “is easily answered in favor of including the final comma, for its omission may cause ambiguities, whereas its inclusion never will.” Garner, A Dictionary of Modern Legal Usage, supra, at 714.
3. Use Commas to Set Off Parenthetical Matter. Comma conventions also require that parenthetical words and phrases be enclosed in commas. Strunk & White, supra, at 2. Commas must surround the year when a date is written as month-day-year and must set off a general geographic place name following a specific one: The March 15, 2015, rodeo in Dallas, Texas, was well attended. Garner, Redbook, supra, § 1.10.
There are other comma usage conventions, some of which stem from editing preferences like the comma-heavy habits of Harold Ross and some of which arise from the writer’s need to direct the flow of the sentence. The next Last Word will address the use of commas with phrases and some cases that have hinged on the placement or omission of these commas.