Apostrophes and Plurals
I've noticed lately that many people seem to be confused about the proper use of apostrophes, so perhaps some people in your organization could use a refresher.
Apostrophes are generally used to signal the possessive or to indicate a contraction. Most people understand contractions, however, so I will mostly ignore that aspect.
Apostrophes and Plurals
Apostrophes Are Not Usually Used to Form Plurals
Some people fail to distinguish between possessives and plurals. How often do I get emails in which people tell me they're "only available on Friday's" or in which they want to send me some "suggestion's." Bad writing is contagious.
One case in which many people confuse possessives with contractions is with the personal pronoun it. "It's," with an apostrophe, is a contraction for "it is." "Its," without an apostrophe, is the possessive form of "it." Here's an example of both uses: "It's obvious that this paragraph should change its focus." One way to remember the rule is to recall that the possessive pronoun "his" has no apostrophe.
Names Ending in -S Can Cause Confusion
The possessive of singular common nouns ending in -s is formed by adding apostrophe-s, as in "boss's." And the plural is formed by adding an apostrophe after the -s, as in "scientists' concerns."
One follows the same rule with proper nouns: it is still customary to write Dickens's or Jones's, a convention one should use unless the resulting word is particularly awkward. Moses's, which already has two -s sounds, fits in this category, and one should write Moses' instead. In this, as in all things, the key is to use common sense.
The plural of proper nouns can be more difficult. I have often seen the equivalent of "the Jones' house." One problem is not recognizing that the plural of Jones is Joneses, as in "the Joneses live down the street." The plural is then formed by adding an apostrophe after the final -s. Thus one would say "the Joneses' house."
Forming the Plural of Acronyms and Numbers
It is now customary to form the plurals of acronyms and numbers by adding -s, with no apostrophe. Thus CPAs and 1980s. What the apostrophe snobs sometimes forget, however, is that until relatively recently, the accepted plurals were CPA's and 1980's, and some people still follow that practice.
You should conform to the modern rule, except where confusion might result, as with single letters or numbers. "Mind your ps and qs," is simply puzzling. The same with "ifs, ands and buts." The single-number problem goes away because, in business writing, one usually writes out the numbers from one to ten. "Too many sevens" isn't particularly challenging.
Joint Possessives Are Fairly Straightforward
If Peggy and Max share an office, you would refer to Peggy and Max's office. If they each have their own office, you would say, Peggy's and Max's offices.
Latin and Greek Plurals Can Be Problematic
The commonest error I encounter is with the various forms of the word alumni. To clarify, one female graduate is an alumna and one male graduate is an alumnus. A group of female graduates are alumnae, and a group of male or mixed graduates are alumni. I constantly see sentences with statements like, "One alumni complained that..."
OK, I understand that most business people didn't study Latin (or Greek) in high school. If it's too much trouble to worry about the difference, just say graduate(s) or even alum(s).
Another common question I hear is about the word data, which is the plural of the Latin word datum. These days, however, one seldom sees the word datum, and data can now be used as either a singular or a plural. You can choose which to make it - just be consistent. Don't say "the data are..." in one place and "the data is..." in another.
Many words have both Latin (or Greek) and English plurals. The plural of index, for example, can be either indices or indexes. If I were writing a scholarly article, I might use indices; if I were writing a business report, I would certainly use indexes. In such cases, you should use what sounds best to you and what is least likely to confuse the reader.
All the best,