Leo Burnett's retirement speech found on his Wikipedia page.

Also, I hadn't heard this fact from Wikipedia: "Burnett's use of the animation medium to sell products was slyly given a nod in the anime series Pokémon. Disguised as muffled backwards dialogue, the character James of Team Rocket, is heard mumbling a line in the grip of a Pokémon's mouth. The line is "Leo Burnett and 4Kids are the devil, Leo Burnett!", mocking both Leo's introduction of animated commercialism, and Pokémon itself, which promotes the Nintendo games of the same title."

Update: the audio. Thanks, Adam!