It's not a synthetic voice.
The uploader comment gives credit to a person named Dean Wendt.
... AM I THE ONLY ONE THRILLED ABOUT AUTO LOREM IPSUM FILLER TEXT
I THINK I AM
BUT I DON'T CARE
I am, sort of. I mean, I usually lorem ipsum in my HTML not in the photoshop mock-up (and even so, it's better to not rely too much on photoshop mockups, better to try doing those directly with CSS) , so I won't be using it that much XD But it's still a very nifty thing.