Mad About Music (1938) directed by Norman Taurog.
At a girls school in Switzerland, neglected and fatherless Deanna Durbin invents a heroic explorer dad for the edification of her friends. Distinguished, affable Herbert Marshall arrives in the nick of time to play the part.
This is the one with the girl's singing and whistling bicycle team. Also a harmonica band and a certain amount of yodeling. Durbin sings "Ave Maria".
It's a pretty average script, elevated by Marshall's dry wit and Durbin's undeniable talent and charm. She's playing 14, but is actually 16 (with top billing!) and seems older. Arthur Treacher is a ranting valet.
Now that I know about Marshall's wooden leg (a WW1 injury) I'm always watching for it. He moves a bit stiffly sometimes.
The soprano voice fell out of favor in pop music, sounding too operatic for the modern ear. Was Durbin part of the last hurrah?
TCM Vault series, available for rent from ClassicFlix.