My Fair Lady: What's this joke in Professor Higgin's first song?

[Schnitte]

@MrAtoz

There isn’t really that much of a pause before the word “set,” at least not as the song is written.

That’s interesting, since in the film version the pause is clearly there (see at 4:27 in this video). Maybe Rex Harrison came up with his own interpretation of that passage that differs from the sheet music.