In what way is the sound motif an important element of Chapter 10?

In Chapter 9, Red tells a story about "one night not long ago" (31) when Samar had come outside to sit beneath its boughs at two in the morning. She had clearly been crying and she was holding a pink cloth with polka dots, which she then tied to Red's lowest branch. The reader assumes that Samar had written her wish on her piece of cloth, as is the neighborhood tradition. But Red has previously told the reader that only if the wisher speaks their wish aloud can Red know the content of the wish. So it is an important moment within the narrative when Samar whispers that she wishes for a friend.