While speaking to The Press of New Zealand recently, long-time Super Mario voice-actor Charles Martinet only occasionally slipped into his Mario voice. But he did so long enough to re-create the lines he spoke that won him Nintendo's top role.
Hello, ima Mario. Okey dokey, letsa make a pizza pie together, you go get somea spaghetti, you go geta some sausage, I getta some sauce, you gonna put some spaghetti on the sausage and the sausage on the pizza, then I'm gonna chasea you with the pizza, then you gonna chasea me with the pizza, and gonaa makea lasagne.'
Martinet confesses that he went on and on, in what he maintains is the only audition he's ever crashed. It got him into Super Mario 64 and other Mario games since then. All the Mario work has gotten Martinet singing Mario songs to himself when he walks down the street—and slipping into Wario's voice when he has a bad day.
While it is unfortunate that the typed word cannot convey the magic of the following bit from the interview—[Martinet breaks out into the voices of Luigi, Wario, Walugi, baby Luigi and baby Mario.] —there is still plenty more good Martinet material to be had in the full article.
Game Junkie's Charles Martinet Interview [The Press, New Zealand]