The way in which the question is phrased is thought provoking. A good case can be made that the two main characters are Melinda and the rest of the world. The entire premise of the novel is for Melinda to emerge into an understanding between herself and the world around her. Melinda is cast as being fundamentally different from the world around her. Melinda is reflective and pensive. Her condition of inward silence enables her to think about the world, which, for its part, is shown is a fast- moving entity in which reflection is absent. The world in terms of the adults and students she encounters lack the reflective element that is so much a part of her own characterization. Her parents are mired in their own challenges which prevent them from fully understanding Melinda's voice and her predicament. Melinda's colleagues find themselves immersed in the realities of high school that preclude them from understanding the person she is and her need to be validated and authenticated. In contrast to this, Melinda is shown as one who grows and seeks to better understand the world and her place in it.
Melinda is able to find her niche within the world when she is able to generate the courage to stand up to "IT" when she is cornered. In finding her voice and being able to "speak," Melinda is able to find her place in the world. She does not fully become a part of it, as her identity has been cast to remain independent of the existential reality of the world. Yet, through being able to speak and articulate her voice, Melinda is able to find some semblance of integration within the world. When she is able to speak to Mr. Freeman at the end of the novel, it is a significant point where the tension and antagonism that had been present between she and the world subsides, if only for a moment.