When "seven swans a-swimmin'" for "seven swans a-swimming" costs Navy Intel Specialist Renee Durette $4,000.
The "a-" beginning makes it seem as though you should be doing Southern American dialect, but "The 12 Days of Christmas" is set in an English aristocratic milieu (with lords and ladies).
More importantly, "Wheel of Fortune" is all about letters, so obviously they've got to be pedantic about getting all the letters.
Anyway... one more reason to be sick of that song. Or do you like it? Here it is by Bela Fleck and the Flecktones.