Another version of the card reads "Super Genius" which Wyle E. also calls himself, exaggerating it as "SOUUU-per" in the early cartoons when he still spoke.
The cartoons in which Wile E. Coyote spoke were not the early ones. In fact, most of them were quite late. There were two separate series: one in which he called himself "super-genius" and opposed Bugs rather than the Road Runner (I think there were four in total), and another series where he was called "Ralph" and his opponent was a sheepdog who fought him bitterly until the factory whistle blew at five o'clock, then they would both punch out their time cards and walk off arm in arm.
I remember them both, and that's what I meant by early, since the cartoons continued to be made well into the 21st Century. The 3 where he speaks with a pompous British accent (and a fourth in another voice) are scattered over a decade, even while the Roadrunner cartoons continued at the same time. It's not unlike how Bugs Bunny switched between several antagonists during the same period, such as Elmer Fudd, Yosemite Sam, and Daffy Duck.
So it's wrong to think of these as series in a linear chronological sense. They were in fact concurrent, but separate series thematically.