The following three style guides are listed as options in the ATA Certification Into-English Grading Standards. Here is my opinion regarding their usefulness for different applications. I have adopted the Chicago Manual of Style for the translation training course I teach. Why?
The Associated Press Stylebook and Briefing on Media Law
(I checked the 2016 edition)
- The first section of the book deals with how to use specific terms.
- Punctuation begins on page 414. (12 pages long)
- Media law begins on page 426.
- This style guide is very useful when searching terminology and its use in the media, as well as media law.
MLA Handbook for Writers of Research Papers
(I checked the 7th Edition)
- The bulk of the book deals with how to write a research paper. It covers how to choose a topic, find sources, etc.
- Chapter 3 deals with the mechanics of writing are covered in chapter 3, from page 63 to page 114 (52 pages).
- This style guide is written for students who are writing research papers at the BA and MA levels.
The Chicago Manual of Style (also known as CMOS or Chicago)
(I checked the hard cover 17th Edition)
- Part 1 deals with the publishing process.
- Part 2 deals with style and usage, from page 223 to page 740 (518 pages).
- Part 3 deals with Source citations and indexes.
- This style guide is the most flexible.
I have seen CMOS referenced much more frequently in discussions that deal with general editing issues. In 2016, when I discussed the ATA Certification Into-English Grading Standards with an ACES expert on style guides, she said it was most like Chicago and it was an excellent style guide.
On the Spanish side, there is an adaptation of Chicago to Spanish: Manual de estilo Chicago Deusto: Edición adaptada al español, published in 2013. Its Spanish grammar section is up to date with the latest version of the RAE and ASALE of 2010. Having two reliable style guides that follow the same format can be very useful for English<>Spanish translators. The Chicago Deusto is worth considering.