Would this voice changing software also have the ability to filter the words and rants comprised of curse words that most parents wouldn't want their kids to hear?
That's almost impossible to do currently. First off, you'd have to write something as complex as Dragon Naturally Speaking transcription software, then you'd have to have each individual person using vox to train the software how to recognize their voice properly, there'd still be errors where things would get missed, there'd be much heavier increased system resources needed to do it, vox communications would be delayed per transmission until the system determine's what's allowed or not, and you'd have constant arguments over what's a swear, what's not, and the softare itself getting confused.
For instance, some people consider bellybutton a swear word. Some people don't. Include bellybutton in filtering, and now you're likely to also block words like assume.
If Vox is big concern, instead of trying to force the rest of the world to block themselves from children's ears, instead, block the children's ears from the rest of the world (i.e. turn off vox).