The human brain is about 1.4 kg and contains over 100 billion neurons. It has four main lobes - frontal, parietal, temporal, and occipital - which control functions like problem-solving, touch, hearing, and vision respectively. The two hemispheres of the brain, left and right, work together but have some specialized functions - the left hemisphere is more logical and analytical while the right is more intuitive and creative. Damage to language areas of the brain can cause aphasia, characterized by difficulties with language production and comprehension. The main types are fluent aphasias like Wernicke's and non-fluent like Broca's, each affecting speech differently based on the location of brain damage