"An investigation into the science of hearing, child language acquisition, neuroplasticity, brain development, and Deaf culture spurred by Lydia Denworth's discovery that her son couldn't hear her lullabies and the family's life-altering decision to give him a cochlear implant. Lydia Denworth's third son, Alex, was almost two when he was diagnosed with profound and progressive hearing loss. As both a science writer and the mother of young children,...