boy’s – possessive for one boy

boys’ – possessive for more than one boy

They sound identical when one says them. The listener has to figure it out from context (the larger meaning of the sentence).

Chris – one kid with the name

Chrises – more than one kid with the name

Chris’s – belongs to one kid named Chris

Chrises’ – belongs to several kids all named Chris

The last three are pronounced as two syllables, and sound identical when spoken.

It would be pronounced just like the plural: boys, not “boyses” (although I like it!).

The added “z” sound at the end is when it is the saxon genitive of a singular ending in s, not plural. And even then, it’s sometimes tricky because it doesn’t always sound right.

For instance:

Q: who does this book belong to?

A: It’s James’ (pronounced Jamses) — ok

At least…I think!

I think if the word ends in an “s” as in “Jesus” that you add the “-es” sound.

However, I stand to be corrected on this.