The document discusses terms related to sensation and speech in the nervous system. It defines anesthesia as the absence of pain or sensation that can result from disease, injury or administration of anesthetic substances. It also defines paresthesia as abnormal burning or tingling sensations, often described as numbness, and hyperesthesia as excessive sensitivity to sensory stimuli like pain or touch. Additionally, it defines aphasia as the absence or impairment of communication through speech, writing or signs due to brain dysfunction, and dysphasia as impaired speech from brain lesions or disorders.