Personally Jim, I've always viewed the origin for the raised back-ridge on Western single-edged swords as being a combination of independent specialization, and popularization of the Turkish (and surrounding regions') sword-making styles. Which may explain why the yelman was sharpened, but most dorsal ridges on Western European swords were not.
But then, who knows?
Anyway, here's a little food for thought: attached are a few images, showing the "Eastern concepts" on European swords.
The first is Polish 18th(?) century.
The second is German dated to 1550.
And the third is an English "scimitar" from the 19th century.