In which Looney Tunes animated cartoon does Wile E. Coyote speak for the first time?

"Operation: Rabbit" is a Looney Tunes animated cartoon first released theatrically in 1952. Directed by Chuck Jones, the cartoon features Bugs Bunny and Wile E. Coyote in the latter character's first attempt to capture and eat the former.

This was the second cartoon to feature Wile E. Coyote (following 1949's Fast and Furry-ous), and the first in which he is identified by his full name. It is also the first in which the Coyote speaks; his voice, like Bugs, was provided by Mel Blanc. The two characters would reappear together in the cartoons "To Hare Is Human" (1956), "Rabbit's Feat" (1960), "Compressed Hare" (1961), and "Hare-Breadth Hurry" (1963).

Set in the desert, "Operation: Rabbit" opens with Wile E. Coyote running up to Bugs Bunny's hole and constructing a door. He knocks on the door and Bugs, slightly bemused by the addition to his property, opens it saying his usual line: "What's up, doc." The Coyote proclaims, in his very first spoken line of dialogue ever, that he is a genius, as well as being faster, taller, and stronger than Bugs, and that he intends to eat the rabbit.