What does melinda hear or imaginary in the book Speak?

In the book "Speak" by Laurie Halse Anderson, Melinda hears her own voice urging her to speak up about the traumatic event that she experienced at a party. She imagines trees as witnesses to her struggle and sees herself as becoming "reinvented" through her art project. These auditory and visual elements symbolize Melinda's journey towards healing and finding her voice.