It may be a grey zone now but I find it likely that judges will decide that copyright does cover the sound of someone's voice and other aspects (intonation, acc

It may be a grey zone now but I find it likely that judges will decide that copyright does cover the sound of someone's voice and other aspects (intonation, accent), as these are vital aspect of the performance and often the reason why a voice actor gets hired. I'd go much farther than that. Unique features of someone's voice and appearance (face, walk) should not only be protected by copyright but also by privacy laws. It would be crazy if producers were allowed to make arbitrary videos with anyone's appearance and voice, putting words in your mouth you'd never endorse. Luckily, this may be one of the cases when politics will react fast and swiftly, if necessary with new laws, since politicians would likely be among the first victims of the new trend.