Use Narrator to read out a play or story with different voices for each of the parts. It uses speech synthesis to read out marked passages using specified voice attributes. You can choose different voices, rates, pitches, inflections, and volumes for each character in the story. The words are highlighted on-screen and there are also a couple of silent read-along options for stage directions, or for you to read out your own parts.
Starting with version 2, you can have multiple chapters in each document to help organize the story, use a word replacement dictionary to fine-tune the pronunciation, and can export the story as an AAC sound file or export it to iTunes, so you can listen on an iPod or iPhone, just like your own audiobook! Plus many other appearance and functionality improvements.
Mac OS X includes several voices built-in, but they are somewhat limited, and only US English. If you'd like more voice talent, including different accents and languages, you can download and try the high quality voices provided by Cepstral LLC or Infovox iVox. Get more information about them on the product page