How is the theme of appearances versus reality used in the novel, El Deafo?

From the neighborhood kids' perspective, Cece appears to be grateful for their choice to turn up the radio. Their misunderstanding occurs because Cece mutters "Uh, thanks" (36), rather than saying what she wishes she could say. Cece tells the reader, "Here's what I wish I could say: Thanks, but I can hear the radio just fine! I just can't understand it, because I can't see the faces of the people who are talking and singing!" (36)