The usual way to make classic cartoons is to record the voices first, and then draw the animation to match. When Robin Williams recorded lines for the Genie in the 1992 film Aladdin, the crew knew that letting him loose with the script would produce magic. Williams recorded hours and hours of sound, playing around with each joke, adding his own ad libs, and doing them all over and over with different recognizable character voices. It had to be a real trip to witness, and a real struggle not to ruin every take with uncontrollable laughing.
Of course, they didn't use all those hours of voice recordings, but they were too funny to discard. They were well worth adding artwork to them anyway. In this video, two directors and the supervising animator from Aladdin remember Robin Williams and bring us the Genie treasures we didn't get to see in the movie.
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