Quotation marks are most commonly used to mark direct speech or identify the words of another author or speaker. Quotation marks can also be used to highlight specific words, express the title of a short literary work, or to emphasize irony.  

Speech

Single or double quotation marks denote either speech or a quotation. Double quotes are preferred in the United States. Regardless, the style of opening and closing quotation marks must match. For example:

• Single quotation marks: 'Good morning, Frank,' said Hal. 
• Double quotation marks: "Good morning, Frank," said Hal.

For speech within speech, use double quotation marks on the outside, and single marks on the inner quotation. For example:

• "Hal said, 'Good morning, Dave,'" recalled Frank.

When quoted text is interrupted, a closing quotation mark is used before the interruption, and an opening quotation mark is used after the interruption. Commas are often used before and after the phrase as well. For example:

• "Hal said everything was going well," noted Frank, "but also that he could use a little help."

Quotation marks are not used for paraphrased speech because a paraphrase is not a direct quote. Quotation marks represent another person's exact words.

Quoting Literature and Research

In most cases, quotations that span multiple paragraphs should be set as block quotations, and thus do not require quotation marks. When quotation marks are used for multiple-paragraph quotations, the convention in English is to give opening quotation marks to the first and each subsequent paragraph, using closing quotation marks only for the final paragraph of the quotation. 

In research papers and literary analyses writers often need to quote a sentence or a phrase. One will need to use quotation marks when quoting authors to show which words are from the other work. Here is an example sentence: 

• When J. K. Rowling began writing the Harry Potter series, she never expected “the boy who lived" to become known worldwide. 

In this example, it is clear that the phrase “the boy who lived” is from J. K. Rowling’s book. 

Titles

As a rule, a whole publication should be italicized. For example, Harry Potter and the Sorcerer's Stone is italicized because it is a book. The titles of sections within a larger publication or of smaller works (such as poems, short stories, named chapters, journal papers, newspaper articles, TV show episodes, editorial sections of websites, etc.) should be written within quotation marks. Thus, when referencing a chapter from the book one would use quotation marks: Harry Potter and the Sorcerer's Stone begins with the chapter entitled "The Chosen One."

Let's explore some other examples. 

• Shakespeare's Romeo and Juliet
• Dahl's "Taste" in Completely Unexpected Tales
• Arthur C. Clarke's "The Sentinel"
• The first chapter of 3001: The Final Odyssey is "Comet Cowboy"
• "Extra-Terrestrial Relays," Wireless World, October 1945
• David Bowie's song "Space Oddity" from the album David Bowie

Nicknames

Quotation marks can also offset a nickname embedded in an actual name, or a false or ironic title embedded in an actual title. For example:

• Nat "King" Cole
• Miles "Tails" Prower
• Dwayne "The Rock" Johnson

Use-Mention Distinctions

Either quotation marks or italics can indicate when a word refers to the word itself rather than its associated concept (i.e., when the word is "mentioned" rather than "used").

• Cheese is derived from milk. [Use]
• Cheese has calcium, protein, and phosphorus. [Use]
• "Cheese" is derived from a word in Old English. [Mention]
• Cheese has three e's. [Mention]

Irony

Quotes indicating verbal irony or another special use are sometimes called scare quotes. For example:

• He shared his "wisdom" with me.
• The lunch lady plopped a glob of "food" onto my tray.

Quotation marks are also sometimes used to indicate that the writer realizes that a word is not being used in its current commonly accepted sense. In these cases, the quotation marks can call attention to slang, special terminology, a neologism, or they can indicate words or phrases that are unusual, colloquial, folksy, startling, humorous, metaphoric, or that contain a pun. For example:

• Crystals somehow "know" which shape to grow into.
• I hope your diving meet goes "swimmingly"!

Using quotation marks in these ways should be avoided when possible.

Punctuating Quotations

In English, question marks and exclamation marks are placed inside or outside quoted material depending on whether they apply to the whole sentence or just the quoted portion. Commonly, they apply to the quoted portion and will be included inside the quotation marks. In some situations, however, the exclamation mark or question mark will apply to the sentence as a whole and will come after the quotation mark. In contrast, colons and semicolons are always placed outside of the quotation marks. Let's explore this punctuation rule further with some examples. 

• Did he say, "Good morning, Dave"? (The question mark does not refer to the phrase within the quotation marks so the question mark is placed outside of the quotation marks.)
• No, he said, "Where are you, Dave?" (Here, the question mark is part of the question posed within the quotation marks.)
• There are three major definitions of the word "gender": vernacular, sociological, and linguistic. (Colons and semicolons always come after the quotation mark.)

In American English, commas and periods are usually placed inside quotation marks, except in the few cases where they may cause serious ambiguity. For example:

• "Carefree," in general, means "free from care or anxiety."
• The name of the song was "Gloria," which many already knew.
• She said she felt "free from care and anxiety."
• "Today," said the Prime Minister, "I feel free from care and anxiety."
• To use a long dash on Wikipedia, type in "—". (Here, the period comes after the quotation mark because quotation marks are used to highlight specifically what should be typed.)

The style used in the UK contains only punctuation used by the original source, placing commas, periods, question marks, and exclamation marks inside or outside quotation marks depending on where they were placed in the material that is being quoted.

• "Carefree" means "free from care or anxiety." (American style)
• "Carefree" means "free from care or anxiety". (British style)