A cochlear implant is an electronic device that is designed to provide hearing to those with severe-to-profound hearing loss. The internal component of the device is surgically implanted into the skull and inner ear with the external piece worn behind the ear. As a prosthetic device, the cochlear implant electrically stimulates the hearing nerve directly, bypassing the damaged part of the inner ear. Many viable nerve fibres remain in the auditory nerve even in cases of profound deafness, and the cochlear implant can restore activity to this nerve and the hearing pathway.

Many individuals who have lost their hearing after acquiring speech and language are capable of excellent speech understanding with their cochlear implant. When young children with profound hearing loss are provided with cochlear implants, they can perceive speech and environmental sounds previously unavailable to them. As they learn to attach meaning to the sounds they are hearing, they build the foundations for spoken language.