Louis Jordan ~ yessss!

Perhaps a bit early for the "R&B" of the rock 'n' roll era, but definitely a major development leading to what came next, right along with vocal-harmony stuff like the Inkspots. Another name for the music typified by Jordan would, I think, be "jump blues." Wonderful happy music!

"Caledonia! Caledonia! What make yo' big head so hard?"

I'm sure that very few listeners (in the US, at least) realized that this fictional woman's name was the Latin word for Scotland!

(I'm also sure most of 'em were too busy jitterbugging to care...)