Q. Why does a comma follow Washington, DC, in running text?

A. That second comma helps to set “DC” off from the surrounding text; together, the commas work like parentheses. (Like parentheses, such commas always come in pairs.) Consider that without the second comma, a misreading is possible. For example, “Washington, DC is a great city” might mean that you are telling someone named Washington that DC is a great city. Another option is to omit both commas: “Washington DC is a great city.” That’s US Postal Service style for mailing labels, but it’s not Chicago style for running text (though maybe one day it will be).

Q. I’m not sure when to use a comma following a date at the beginning of a sentence. Can you help? For example, “In the 1960s, McManus declared victory . . .” or “In 1967, McManus selected Jones as the victor . . .” A fellow editor suggests striking all of the commas that follow the dates. 

A. Your editor friend’s suggestion is reasonable, and Chicago recommends much the same approach (see CMOS 6.31). But it’s also reasonable to disagree in certain cases. Wherever a comma might be helpful for clarity (or for emphasis), add one: for example, “By 1967, 357 residents had returned to the complex.” (That comma keeps the numerals from appearing to run together.) In general, a flexible approach will serve the reader better than a rigid one.

Q. I’m a Spanish–English translator, mostly in the arts. Citations in Spanish often include the place of publication of a journal. This is not mentioned in the Manual (as far as I can see). Any thoughts on this?

A. According to CMOS 14.182, the place or institution where a journal is published may be added if the journal might be confused with a similar title, or if the title might be unfamiliar to readers. You could omit this information then (even if it occurs in the original citation) for titles that are well known (or easy to locate online). Otherwise it may be retained in parentheses, following the title of the journal. The following example includes the name of the university that publishes the journal:

Palacios Sanz, José Ignacio. “Evolución, espacios y contenidos del archivo y de la librería musical de la catedral de Burgo de Osma.” Anuario de Historia de la Iglesia (Universidad de Navarra) 27 (2018): 297–323.

The Palacios Sanz article conveniently includes an English-language title and abstract, so you could instead present the citation as follows (see also CMOS 14.99):

Palacios Sanz, José Ignacio. “Development, Spaces and Contents of the Archive and Music Library of the Cathedral of Burgo de Osma.” [In Spanish.] Anuario de Historia de la Iglesia (University of Navarre) 27 (2018): 297–323.

Q. Hi, I was just wondering, how do you format the citation for a translated work if the name of the translator is not known?

A. For a book, you could adapt the usual format for translated titles (see CMOS 14.104), substituting information about the translation for the translator’s name. The fact that the name of the translator is not known could be added in square brackets. (Adapt as needed for other types of sources.)

Last Name, First Name. Title of Book in English. Translated from the Russian [translator unknown]. Chicago: University of Chicago Press, 1972.

The definite article in “Translated from the Russian” is conventional (it implies “from the Russian edition” or “from the Russian text”). Some editors will choose to omit it.

Q. Is the serial/Oxford comma generally used in British English? If the guidelines do not specify anything, what would be the appropriate usage?

A. You would think that the Oxford (or serial) comma would be popular in British English. And it is, but it’s not exactly British law.

The latest iteration of Oxford’s venerable style guide (New Hart’s Rules, 2nd ed., 2014; this guide, like Chicago’s, has its origins in the 1890s) supports its use but allows it to be omitted: “For a century it has been a part of Oxford University Press style to retain or impose this last comma consistently, to the extent that the convention has also come to be called the Oxford comma. . . . The general rule is that one style or the other should be used consistently. However, the last comma can serve to resolve ambiguity” (p. 77). Butcher’s Copy-Editing, published by Cambridge University Press (4th ed., 2006), likewise treats serial commas as optional: “A comma should be consistently omitted or included before the final ‘and’ or ‘or’ in lists of three or more items” (p. 156).

In its own text, the guide by Cambridge omits serial commas; Oxford’s retains them.

So for British English, use serial commas or omit them, but do so consistently. And if you go without, make sure to add a comma wherever its absence might create ambiguity.

Q. I’m wondering about omitting the periods for US Department of Energy. On its site, it’s U.S. Do we follow the department’s preference or Chicago style?

A. The name of the organization is the United States Department of Energy. When you follow Chicago style to write “US Department of Energy,” you are abbreviating the fuller form of the name. The abbreviation at Energy.gov probably follows the GPO Style Manual, published by the US Government Publishing Office. GPO style uses periods in “U.S.” (and “U.K.” and the like), and those periods are a matter of government style. But unless you’re writing for the government, it is safe to omit them.

Q. It’s my observation that increasingly, in a sentence like this, the commas are being omitted, no matter how many sisters there are: “I wanted to go to the store, but my sister Sara refused.” Can’t we just admit that it’s cleaner and easier to omit them most of the time, unless there’s genuinely a clarity issue? The world is changing; can we make this official? Thank you.

A. In casual correspondence and the like, it’s OK to omit such commas wherever details related to family composition are unimportant or irrelevant (in other words, most of the time). So “my sister Sara” is totally fine in casual usage even if Sara is your only sister (and therefore functioning as a nonrestrictive appositive, which would normally be set off by commas). Consider that official. In more formal prose, however, these commas can be important. In a work of history or a biography—where the presence or absence of commas will help readers follow the narrative—they are essential. In other types of works, the rule can often be relaxed. (That’s not an official ruling, but it is a practical one.) For more on restrictive versus nonrestrictive appositives, see CMOS 6.28.