Good morning, Julie, I live in Germany, and "The Sound of Music" is hardly known here (Ditto Mary Poppins). I have heard, too, that whilst busloads of Brits and Americans go to Salzburg for special SoM holidays, they are welcomed as tourists, but the locals are puzzled by the fascination with the place and the film.
Why do you think it is such a success only in the Anglophone world? Were songs translated in the foreign-language versions and sung by other people, as sometimes happens with big musical films? If so, that just goes to show how much you and your voice were responsible for the popularity and long-lived success of the film.
Congratulations on all your work and on your continuing success (PS - I loved "Despicable Me"!)