Professor Layton's role might just be the most difficult; his voice is naturally rather deep, and what I believe to be a Scottish accent (correct me if I'm wrong). What makes it most complicated is the fact that his voice must be much more explosive in this interpretation, while maintaining the accent and poise. Just know that if you're casted for this, I officially consider you a Saint.

A sample of his voice can be found right here.

It is an Azran Legacy spoiler, so proceed with caution!