This sounds like the unlikely topical confluence of Microsoft, censorship, and the often broken and abused US Patent system.

This actually sounds like a great idea if they could successfully apply it to Xbox Live. It's not like it doesn't happen already online in chat rooms and MMOs. I think there's an obvious fear that this would fall into the government's hands though, especially if they can play well-synthesized voice in place of something objectionable and do it transparently. Fortunately I don't think it's going to happen for a few more years.