This. I would assume copying a voice pattern is treated no different from copying an appearance. If a 3D model is a very close approximation to a particular person's face and you use it in a game intentionally to benefit from that person's likeness, you can run into legal issues. And of course you really open yourself up for a lawsuit if you then attach the real person's name to it.

EDIT: See the NPR Planet Money podcast linked elsewhere in the comments. Apparently there are fairly specific laws to protect someone's likeness -- including their voice -- thanks to the entertainment industry and Frank Sinatra.

Tom Waits sued for this reason multiple times [1].

I guess he had a strong case because in all three cases he was (or so he claimed) approached to do a commercial and the advertisers went with a Waits-like surrogate after he declined.

https://en.wikipedia.org/wiki/Tom_Waits#Lawsuits