How come is the word "sound" used twice in one sentence?
The word "sound" is used twice in this sentence because it is used to refer to two different things. The first use of "sound" is used to describe the overall sound that she is hearing. The second use of "sound" is used to describe the sound of magical fairy dust. Since she doesn't know that the sound of magical fairy dust is what she heard, she uses the word "sound" twice to compare what she heard with a different sound.