"There wasn't any precedent in movies for a character like a robot that was to be so expressive, but not using words in English or any language," Burtt explains. "And I went to synthesizers at first, but the results sounded too much like a machine, just something cold - it didn't seem to have a soul." Burtt tried lots of approaches. He "auditioned" plenty of noise-making doodads. After a while, he and Lucas realized that as they'd struggled to define what they wanted to hear, they'd developed a repertoire of funny little bleeping noises - verbal sounds that were beginning to take on the characteristics of a language. "And suddenly one day I realized, 'Well, why don't we just do something like that?'" Burtt says. "And so I began to make my own sounds."