Could We Hear the Speaking Voice of a 6-Inch Tall Human?

MetaFilter member David Provost poses some interesting questions of biology and physics:
I am considering writing a novel/story that involves the idea of people living among us who are somewhere between three and eight inches tall, but I don't know enough about the physics of sound to know if normal height humans would be able to speak to these tiny people. Would their voices be too high-pitched to hear at all, or just very difficult to understand? Would our voices be understandable to them?
How would you answer him?
Link | Image: The Borrowers by Working Title Films
























