Them's fighting words!

A friend decided to help settle the dilemma-dilemna question below by sending a note to the etymologist at the Oxford English Dictionary. Here is her note:

To: Anatoly Liberman
Oxford Etymologist
Oxford University Press

Dear Mr. Liberman,
Reading your delightful blog makes me wonder this: many Americans -- highly educated ones -- between the ages of 50 and 65 were taught to spell dilemma with an n, "dilemna." It appears to be most common in the Northeast.

Do you have any idea why? Or thoughts?
Curiously yours,

The reply:

I Googled for DILEMNA!

My goodness! DILEMNA is known all over the English speaking world, from America to Australia, and no one has an idea where it originated. On the other hand, I am not alone: lots of people have never heard that this idiotic spelling exists.