According to one of my previous articles, whenever a Southerner
says "Y'all watch this," get out of the way because those are
probably the last words he will ever say.

Well, I'm a Southerner. I used to live in the southeastern
United States, but I moved to the southeast of China. And, I'm
about to say the magic words:

Y'all watch this.

The word is "week." If I want to talk about more than one week,
like what I wrote a few weeks ago, I'll use weeks. No apostrophe.
If I want to talk about something belonging to a week, such as
"last week's newsletter," I'll use an apostrophe.

That's the rule. If it's a noun, s makes it plural and
apostrophe-s makes it possessive. It's just that simple.

If I were still in the US, and I wanted one of those fancy
carved signs that are so common on southern lawns, it would not
read "The LaRocca's." The LaRocca's what? His lawn? His sign?
That apostrophe makes it singular possessive, so The LaRocca
(one person) is surely claiming ownership of something. If that
wasn't his intent, and he whacked in an apostrophe anyway, he's
an idiot.

What about plural possessive? Is it "the LaRoccas' house" or
"the LaRoccas's house?" Well, it's neither, since my wife isn't
a LaRocca and we don't own a house. But for the sake of this
article, pretend she is and we do.

In ON WRITING, Stephen King swears it's LaRoccas's. When I was a
student, my teachers swore it was LaRoccas'. As an editor, I've
heard the first was US standard and the second was UK standard.
And the answer is, I don't care. Just be consistent.

I once met an editor who said that the spelling determines
pronunciation. She's an idiot. Spelling isn't all pronunciation.
It's also history. I'll say LaRoccas-zz whether it's LaRoccas' or
LaRoccas's. So will you.

Jump up five paragraphs and read the seventh word. Noun. Note
that I didn't write pronoun. Just for fun, the rule for pronouns
and apostrophes is completely different.

It's is a contraction for "it is" and its is possessive. Who's
is a contraction for "who is" and whose is possessive. There's
is a contraction for "there is" and theirs is possessive. Etc.
Possessive pronouns never use apostrophes. Its, whose, your,
yours, their, theirs...

And there you have it. Apostrophe usage made simple.