Quotation marks are signposts indicating that spoken or written words are being expressed. They have other purposes, too, but this post confines itself to this role.
Despite the ubiquity of quotation marks, some people still err in placement of the closing mark. Generally, a close quotation mark follows rather than precedes a sentence’s terminal punctuation, as in the sentence “You have nothing to worry about.” (Styles for quotation marks in British English differ from those for American English: Terminal punctuation follows the close quotation mark, and dialogue and quotations are enclosed in pairs of single, not double, quotation marks.)
Notice, however, that I wrote “generally,” and not just because of the British English exception. (As you see here, a comma, like a period, is located inside quotation marks when it follows one or more words thus confined.) What are the exceptions? If the terminal punctuation mark is a question mark or an exclamation mark, and it appears outside the context of the quotation, it should be located outside the quotation mark as well.
(In the examples below, which I enclose in double quotation marks because they are themselves excerpts of written documents, the sentences in question are bracketed by single quotation marks — the correct style for a quote of a quote.)
For example, notice the placement of the question mark in “Who said, ‘You have nothing to worry about’?” The framing sentence, not the quotation, is an interrogative sentence, so the question mark belongs outside the single quotation marks bracketing the quotation (but inside the double quotation marks, because it is part of my example.) By the same token, in the sentence “I can’t believe he had the nerve to say, ‘You have nothing to worry about’!” the indignation resides in the context of the framing sentence, not in the recitation of another person’s contentious comment.
Notice also that, though a period would ordinarily be located within the quotation followed by the question mark and a comma would usually appear after “about” in the example with the exclamation point, quotation marks and exclamation points trump and replace periods and commas in such sentence constructions. Punctuation marks are never paired (except in the use of multiple question marks or exclamation points in informal writing, and in the case of a close parenthesis and a period, like the tag team you see right here).
That’s not all there is to quotation marks, of course. For example, in a future post, I’ll discuss the subtleties of proper placement of attributions, those identifying phrases such as “he said” or “she added” so fundamental to both journalism and literature.