For his bubbly fish story, writer-director Andrew Stanton paired Albert Brooks’s depressive Marlin — you’d be a gloomy Gus too if your wife had just been devoured and your son was missing — with DeGeneres as the perky, amnesiac Dory. Stanton became such a student of the comedienne’s stumbling speech patterns that her dialogue sounds true to herself and Dory, and delightfully spontaneous. That’s writing! Also directing and acting.