Just talked to my mate about this and posed a question;

Let's say we both have the exact same voice;

If I chose to sell the rights to use my voice, would I be infringing on her right to not have her voice used?

What if I sold the rights to use my voice to be used to make statements which she fundamentally disagreed with and which could be attributed to her by people who weren't aware of the provenance of the voice being used?

The tech throws up all sorts of ethical questions, beyond anything legal. The next few years is going to be interesting as this is explored. There's going to be some mad fringe cases which make people stop and wonder what the limits are when it comes to artificial replication of characteristics.