Companies are of course experimenting with this. And the mod communities are working on projects too. A Fallout 4 mod is using AI to voice human written option

Companies are of course experimenting with this. And the mod communities are working on projects too. A Fallout 4 mod is using AI to voice human written options in the same voices as existing characters. And there's a couple Skyrim projects working on dialogue generation. Personally I expect this to be an area where amateurs/hobbyists contribute quite a bit of research.