A Key Feature of Viewer 2.1 (now available for test download as version 2.02) is the ability to morph voices as a wide range of characters. This should come in handy for all the escorts around Second Life who are roleplaying as females and have either had to raise their natural pitch or use a voice swtich in order to fool their customers. The only other option is the rather uncomfortable process of castration, which many seek to avoid.
You will need to pay 750 Linden a month to access the voice packs. There are 25 voices morphs available.
You can download the test version (look for test viewer) here: https://secure-web38.secondlife.com/my/support/downloads/
You can read about the test viewer, and other enhanced capabilities including enhanced camera properties here:
Real Life picture of delighted Zindra Escort hearing the good news about voice morphing!
Second Life persona below.