In English, there are two main styles of quotation marks (which are also called inverted commas and quotes). American writers routinely use double quotation marks, “which are pictured to the left and look like the marks around this clause.” Writers in the U.K., Australia, etc. may use either single or double quotation marks, with the former typical of academic publications especially and the latter commonly found in online media. The single quotes ‘look like the marks around this phrase.’
Uses of quotation marks
Quotation marks have five main uses.
1. Use quotation marks when quoting someone—for example:
Ralph asked, “Should we build a fire?”
2. Use quotation marks when referring to a word as a word:
I asked what he meant by the word “built.”
3. Use quotation marks when you want to imply that the quoted word or phrase is dubious:
You could listen to the “experts,” or you could just do what makes sense.
4. Use them when you’re coining a new word or phrase, but only on the first use:
Despite obvious appeal, Lululemon is what I like to call a “cult stock.” [The Street]
5. Use quotation marks around the titles of articles, poems, short stories, songs, and TV shows. Larger works are italicized (as is Harmonium, the book of poems by Wallace Stevens, in the following quote).
This poem, together with the early “Sunday Morning” and “Le Monocle de Mon Oncle,” proved key to Stevens’s volume Harmonium when it was published in 1923. [Poetry Foundation]
Quotes within quotes
For a quote within a larger quote, American writers use single quotation marks inside double marks—for example:
He said, “My favorite poem is ‘Sunday Morning’ by Wallace Stevens.”
In British and Australian English, it’s the opposite—for example:
He said, ‘My favorite poem is “Sunday morning” by Wallace Stevens.’
For quotes within quotes within quotes, etc., keep alternating single and double.
Punctuation inside or outside quotation marks?
In American English, most writers place periods and commas inside quotation marks regardless of the period’s or comma‘s relationship to what’s being quoted—for example:
My favorite poem is “Sunday Morning.”
In British and Australian English, it’s the opposite:
My favorite poem is ‘Sunday Morning’.
But all standards agree in their treatment of question marks and exclamation points with quotation marks. If the mark is part of what’s being quoted, it goes inside the quotation marks:
She asked, “Have you ever been to Paris?”
If it’s not part of what’s being quoted, it goes outside the quotation marks:
Have you ever read “Sunday morning”?
There are three things I love about “Sunday Morning”: its images, its sound, and its emotion.
Unnecessary quotation marks
The unnecessary use of quotation marks is a sign of amateurish writing. In business writing and in poorly written web articles, some writers use quotation marks to give emphasis—for example:
Most people already know full well that proper diet and exercise is the way to lose weight, and yet so many find themselves helpless to do what they know they “should” be doing. [ArticlesBase (article now offline)]
Some writers put unnecessary quotation marks around expressions or common phrases—for example:
Be patient and “roll with the punches.” [EZine Articles (article now offline)]
When change comes it is best if we “get with the program”. [iSnare]
And some writers use quotation marks for phrasal adjectives that should be hyphenated—for example:
This “back to the basics” [back-to-the-basics] approach resonated with fans and critics alike … [Pop Matters]
Fans of the “everything and kitchen sink” [everything-and-kitchen-sink] approach will love this offering from Panasonic. [Hub Pages]