"There was nothing but Mo's voice and the pictures forming in their minds from the letters on the page"

The author, Cornelia Funke, has often said that she imagines Mo's voice to be exactly like that of the actor Brendan Fraser, and it's Fraser who plays Mo in the Inkheart movie. To listen to the voice that Funke based Mo's reading on, here's a clip from an interview about the Inkheart movie.