The structure of the human ear that develops abnormally in a person with Pendred syndrome is

the cochlea, which is a spiral-shaped structure in the inner ear responsible for processing sound signals. In individuals with Pendred syndrome, the cochlea may be malformed or underdeveloped, leading to hearing loss and other auditory abnormalities. Additionally, the vestibular system, which is responsible for balance and spatial orientation, may also be affected in individuals with Pendred syndrome, leading to issues with balance and coordination.