Japan Acoustic Lab has analyzed the skeletal structures of Mona Lisa and Leonardo da Vinci, in order to replicate the sound of their voices:
We believe we were able to create the voices that are very close to the real voices. Perhaps it was really how they really sounded," the lab's chief Matsumi Suzuki says on the website. ...
Suzuki says he gave Mona Lisa a slightly nasal tone because of her relatively large nose.
For Leonardo, Suzuki made his voice around the time when he was 60 years old to match his bearded face in the famous sketched portrait.
"Because the beard covers his jaws in his portrait, we could not tell his exact skeletal features. We assumed that he had a heavy-jowled face, giving him a nice, bass tone," Suzuki says.
The whole thing, of course, is part of the promotion of Ron Howard's Da Vinci Code movie.