Cat with a painfully quiet meow

My girlfriend and I took in a very special kitty a couple of years ago.  She had a rough life, her original owner and his rotten kids abused her quite a bit and then abandoned her.  So our neighbor across the street fed her for a while, but they had to move.  So we took her in.  She had almost gone feral by that time.  Now, she's our roly-poly kissy kitty.  She's a wonderful cat, very affectionate.  I have noticed that she has an almost painful sounding meow, when we can actually hear it.  She also doesn't purr very loudly at all.  I am wondering if she could have had her vocal cords hurt by her original owners.

Possibly, but probably not. Some cats are just quieter than others. We have one who we honestly thought might not have any voice at all, but he has slowly become mor expressive. But it has taken 11 years!

Some cats are simply "soft-spoken", while others are "screechers". Like mrblanche said, it can change over the course of a lifetime, too.

I agree.  My kitty Zoe has the most adorable little squeak.  I've never heard a full 'meow' out of her in five years.  Another of our guys, Ozzy, was a bit traumatized when we got him from the shelter, we'll never know why.  He has the tiniest little meow ever--the first time I heard him really let it go was on the way to the vet--it turns out he can belt out a meow when he feels the need!  But otherwise, we almost never hear it. 

Lucky kitty to have been taken in by you two!