In the Novel Micheal meets a woman(I can't remember who it was I think his Nanny), during his stay on Sicily. She tells him the story about Luca Brasi. Does anyone know why it isn't included in the film?

I have also found the song "Speak softly Love" and I wonder why it's with vocals, because there's no sung version of the Godfather's theme in the film. Can anyone explain that to me?