Every time I think it’s useless to rehash basic GUMmy stuff, something happens to prove me wrong. This time it was seeing an incorrectly formed plural possessive of a proper noun in a published children’s book.

I saw red.

So, I’m writing what’s sure to become the first in an informal series on the basics. Welcome, and I hope you enjoy the ride.

First, let’s talk about plural formation. There are two basic types: regular and irregular. A regular plural simply adds -s or -es to the singular form, like this:

house/houses

car/cars

An irregular plural sometimes changes the form of the noun, like this:

goose/geese

mouse/mice

die/dice

But sometimes, it doesn’t change at all.

deer/deer

moose/moose

Now, what if we need to form a possessive of those plurals?

Well, for the regularly formed plurals, we only have to add an apostrophe. That’s how it’s done. Honest. Just an apostrophe.

houses’ (as in “All those houses’ exteriors will be repainted according to the HOA’s specifications”)

cars’ (as in “Their cars’ bumpers were torn off in the collision”)

But for the irregularly formed plurals, we need to add an apostrophe and an S.

geese’s (as in “The geese’s diet was organic”)

mice’s (as in “The mice’s blood was sampled every six hours”)

dice’s (as in “The dice’s results were suspect”)

deer’s (as in “The three deer’s hides were tanned behind the cabin”)

moose’s (as in “I heard those moose’s bellows from all the way down by the river”)

Now, what about a proper term, like Taino? That’s the name of the indigenous people Columbus met when he landed in 1492. In the free version of the online Merriam-Webster dictionary, it states that the plural is either “Taino” or “Tainos.” The first one’s irregular (the form doesn’t change at all), and the second is regular (just adding an S). Form the possessives according to the rules: Taino’s OR Tainos’. Context helps the reader know when “Taino’s” is plural. (And if it doesn’t, it should.)

Similarly, if your surname is Dickens, a number of you are the Dickenses. Together, all of you live in the Dickenses’ house. (Sure, you can say “there’s the Dickens house,” but the meaning’s not the same, and it totally misses the point of this post.) It’s a regular plural that adds -es to the singular form, so you use only an apostrophe to form the plural possessive. We’re the Conlins. Our house is the Conlins’ house. Regularly formed plural takes only an apostrophe.

There are no stylistic variations for forming plural possessives. This isn’t a guideline; it’s a rule.

There you have the basics. Remember, this is only for plural possessives. If we need a refresher on forming possessives of proper names like “James,” I’ll cover that in a separate post. (Hint: there are stylistic variations for forming proper singular possessives.)