Jonah: There is an extensive and fascinating discussion of points like this
in Steven Pinker’s book The Language Instinct. He goes into detail about
such things as why the plural of “Walkman” is “Walkmans” (not “Walkmen”),
and why the past tense of “to fly out” is “flied out” (not “flew out”). He
also retails that fine old joke about the lady who gets into a taxi in
Boston and asks the driver if he knows a place where she can get scrod.
“Jeez, that’s the first time I’ve heard it in the pluperfect subjunctive…”