Use double quotation marks around short quotations integrated into your prose—that is, those not set as block quotations. When quotation marks appear in the source itself, convert them to single quotation marks so that they are distinguished from your own.
In the poem “Memories of West Street and Lepke,” Robert Lowell, a conscientious objector (or “C.O.”), recounts meeting a Jehovah’s Witness in prison: “‘Are you a C.O.?’ I asked a fellow jailbird. / ‘No,’ he answered, ‘I’m a J.W.’” (38–39).
In Bilingual, François Grosjean explains that “in the sentence ‘Look at the corns on that animal,’ the meaning of the French word cornes (horns) has been added to that of the English word ‘corn’” (70).
When your quotation consists entirely of material enclosed by quotation marks in the source work, usually one pair of double quotation marks is sufficient, provided that the introductory wording makes clear the special character of the quoted material.
Meeting a fellow prisoner, Lowell asks, “Are you a C.O.?” (38).
Since block quotations do not appear in quotation marks, quotation marks that you reproduce from the source can be rendered as double quotation marks.
Block quotation (verse)
In the poem “Memories of West Street and Lepke,” Robert Lowell, a conscientious objector (or “C.O.”), recounts meeting a Jehovah’s Witness in prison:
I was so out of things, I’d never heard
of the Jehovah’s Witnesses.
“Are you a C.O.?” I asked a fellow jailbird.
“No,” he answered, “I’m a J.W.” (lines 36–39)
Block quotation (prose)
In Bilingual, François Grosjean notes:
A more subtle type of lexical reference—the bête noire, so to speak, of bilinguals—is similar to a loanshift, where only the meaning of the word is brought in and added to an existing word. For example, in the sentence “Look at the corns on that animal,” the meaning of the French word cornes (horns) has been added to that of the English word “corn.” (70)
When to use block quotations: 6.35, 6.38.
Source: MLA Handbook 9