A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Plurals - General rule
Spelling
Part III. Style 20 spelling

Model your spelling on American usage and be consistent, except in quotations, where you should usually follow the original spelling exactly (see chapter 25). When in doubt, consult a dictionary. Be aware, however, that dictionaries often differ on how to spell the same word and that some are more accurate and up-to-date than others.

The most reliable authority for spelling is Webster's Third New International Dictionary or its abridgment, the eleventh edition of Merriam-Webster's Collegiate Dictionary. The abridgment is available in book, CDROM, and Web-based formats. For the names of people and places, see the listings at the end of Webster's or the separate publications Merriam-Webster's Biographical Dictionary and Merriam-Webster's Geographical Dictionary.

Where Webster's offers a choice between spellings, use the following principles to select one: where variants are separated by or, choose either one and use it consistently; where variants are separated by also, use the first. If the preferred spelling in Webster's differs from the conventional one in your discipline, follow the spelling of the discipline. For style guides in various disciplines, see the bibliography.

The spell-checking feature in most word processors can catch certain spelling errors but not others. It will not recognize, for example, that you typed and when you meant an, or quite instead of quiet. It will probably not help with proper nouns or foreign terms, and it may lead you to make global spelling changes that in some cases are inaccurate. A spell-checker is not a substitute for a good dictionary or careful proofreading.

This chapter offers general guidelines for spellings not found in most dictionaries. If you are writing a thesis or dissertation, your department or university may have specific requirements for spelling (including use of particular dictionaries). Those requirements are usually available from the office of theses and dissertations. If you are writing a class paper, your instructor may also ask you to follow certain principles of spelling. Review these requirements before you prepare your paper. They take precedence over the guidelines suggested here.

20.1 Plurals

20.1.1 General rule

For most common nouns, form the plural by adding s (or es, for words ending in ch, j, s, sh, x, or z). Most dictionaries give plural forms only for words that do not follow the general rule.

The general rule applies to the names of persons and to other proper nouns, including Native American tribes. If such a noun ends in y, do not change the y to ie, as required for common nouns. (Do not confuse plural forms with possessives, which are described in 20.2).

the Costellos

the Frys (not the Fries)

the Rodriguezes

the two Germanys

the Hopis of Arizona (not the Hopi)