Authors often mention to me that they are confused about whether to use double or single quotation marks in their quoted material. The answer depends on whether you are writing in US English or British English. I’ll explain the difference first and then provide an example of the usage.
In US English, it is standard to use double quotation marks first and then single quotation marks for quotes within the quotes. In British English the system is reversed, so if you read literature from the UK or countries that tend to follow British style in their English (e.g., many European countries, Canada, India), you will likely see single quotation marks being used as the primary marks and double quotation marks being used for quotes within quotes.
Because scholars often read literature from many places, it can be quite confusing to know which system to use in their own writing. You should use the style expected by your readership so for instance, if you are submitting an article to a journal that asks for a US style (e.g., APA, Chicago, MLA), then use the US system. For more on US usage, see the Chicago Manual of Style, and for more on British Usage, see the New Oxford Style Manual.
Okay, let’s proceed to our example. I will give the example in US style because it is more natural for me, but basically, in the British system, all of the double quotation marks would be single quotation marks, and all of the single quotation marks would be double quotation marks.
Imaginary Original Text
Let’s imagine that we came across the following sentences in a book. I have intentionally kept the ideas simple to avoid sentence clutter so that we can focus on the target issue here.
In the original wording, the word sad is placed in quotation marks because it is being used ironically, and the second sentence contains a quote.
Our Imaginary Quotation of the Original Text
If we wanted to quote these sentences in our own work, we would have to add double quotation marks around the whole thing. But if we just stop after adding the double quotation marks at the beginning and end, the quote will be confusing to read because of the internal quotation marks:
So we have to change the internal quotation marks to single quotation marks to tell the reader that those marks were found in the original, like this:
Returning to our example, we can improve it a bit more by adding some introductory wording before the quote to place it within the context of our discussion (after all, we are quoting to enhance our discussion, not replace it!). Here is how our final text might look: