Nerd: Seems to me "Maggie D." is simpler and more familiar than "Maggadee," so it's strange to begin with that "Maggadee" would come into existence at all.

John: I think that someone who didn't *know* that "Maggie D" was what was being sung could, and probably would, hear it as "Maggadee" and not guess that it was "Maggie D." *Neither* of these is familiar. In Neal Pattman's case, we don't know whether or not his father was as baffled about the name as Neal, who, according to his own statement, simply sings it as he heard his father do it.

What is the probability that "Maggadee" would somehow arise spontaneously?

What is a plausible source other than "Maggie D"?