Early in the mary poppins making-of pic Saving Mr. Banks (in wide release Dec. 20), the songwriting brothers Richard and Robert Sherman make up a word--but not that one. The word is responstable, which rhymes with constable. But Poppins author P.L. Travers (Emma Thompson) frowns on such frivolity and tells the Shermans (Jason Schwartzman and B.J. Novak) to "un--make it up." They quickly hide the music to another song they're working on, "Supercalifragilisticexpialidocious."
"Rest assured that this was the way it was," says the real Richard Sherman, now 85 and a consultant on the film. (Robert died in 2012.) The brothers...