Citation, Documentation of Sources

Q. When working with references in different languages when the main text is in English, do you indicate editors, translators, and so forth in English or in the language the book was written in (e.g., German)?

A. It’s best if everything is in English, but if that requires guessing at the translation of words in an unfamiliar language, it’s better to leave the citation as is.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]