Louise, I suspect this may already be old news to you, but just in case - an article about the original "Yon Yohnson" character and the 19th Century play in which he first appeared:
http://sahswi.org/bits-and-pieces-of-swedish-american-history/More on Gus Heege who wrote and starred in the Swedish immigrant trilogy
Ole Olson (1889),
Yon Yonson (1890) and
Yenuine Yentleman (1895):
http://en.wikipedia.org/wiki/Gus_HeegeAnd there is the neverending "Yon Yonson", quoted by Kurt Vonnegut in "Slaughterhouse Five":
http://en.wikipedia.org/wiki/Yon_YonsonAll this would have been before El's time, but these early productions and songs may still have directly or indirectly influenced him.
As a sidenote, I'm sure it's not easy for outsiders to distinguish between Swedish and Norwegian pronunciations of English, but for us natives there is a clear difference. I once read a joke, said to originate from the 1800s, that went something like this:
Sven the Swede and Lars the Norwegian enter a saloon. "What'll you have, gents?" asks the bartender. "I'll have
yin, please," says Sven, and everyone in the saloon laughs. Lars says, "I must apologize for my friend here. Like me, he's lived in the States for over thirty years, and he still hasn't learned to pronounce
shin correctly."