[On page 42 in John Grant’s book “Encyclopedia of Walt Disney’s Animated Characters” there is a still from the film “Mickey’s Delayed Date” (1947), where the author asks; “Can you decode the posters behind?”
The pencil drawing for the same background, which can be found at the “Cowan Collection”:
gives some answers, since most words here are spelled backward, but not everything is explained in the blog posting.
After studying the pencil drawing, I “cracked” it.
The “decoded” text on the middle poster is:
TUES NITE (= Tuesday night)
JITTER BUG (= Jitterbug, the swing dance)
«Orsayday and his Orchestra», on the poster far right, is a spoof of “Tommy Dorsey and his Orchestra”, a popular big band in America at that time.
“Orsayday” is «Dorsay» («Dorsey») in pig latin.]