Initially, Burtt’s work seminal voice-acting as R2-D2 was just a reference point for Stanton’s vision of Wall-E. Speaking with The Hollywood Reporter, he admitted to badgering producer Jim Morris about getting the voice as close in spirit to the “Star Wars” droid’s own whimsical sounds. “I kept saying for about two years to my producer: ‘I need it like R2-D2! I need it like R2-D2,'” Stanton explained until finally, they did just that. But there was one slight wrinkle: according to the “Wall-E” production notes, after finishing work on “Revenge of the Sith,” Burtt had sworn off doing anything remotely similar ever again. “No more robots,” he reportedly told his wife not long before he was asked to join “Wall-E.” Luckily for Stanton and anyone else who loves the film, Burtt quickly changed his mind when he realized how different an experience it would be from making “Star Wars.”
“Fortunately, it was such a fresh and exciting idea, and the challenge of the sound in the film really appealed to me. Sound and the robot voices were going to play such an unusual role that I couldn’t help but be inspired. So, of course, I signed on to work with Jim and Andrew and do the sound design for the film.”
As part of his first animated feature, Burtt would prove to be far more invaluable to the film than Stanton or anyone else could possibly realize. Not only did he provide the voices for Wall-E, M-O, and Auto — he was also responsible for the rest of the film’s sound effects. Creating a library of 2,400 files that surpassed in size even his work on “Star Wars.” Apart from his prolific work, one of Stanton’s other reasons for wanting Burtt was his knack for making the lifeless spectacularly personable.