Deafness

The word deaf, can have very different meanings based on the background of the person speaking or the context in which the word is used. The term is commonly used to mean having profound hearing impairment, a physiological condition causing an inability to receive or process aural stimulation, i.e., sound.

Depending on the definition of deafness used, the global deaf population is estimated to be roughly 0.1% of the total population (1 in 1000). The figure is likely to be higher in developing countries than developed countries due to restricted access to health care. Worldwide, at least 5% (1 in 20) are estimated to have a hearing problem great enough to cause them some difficulty. The great majority of people with hearing impairments are elderly or acquired hearing loss after leaving school.

A significant minority of deaf people are part of Deaf culture. They are mostly either individuals who were born deaf or became deaf at an early age, and who have a "severe or profound hearing loss"; they can also be children of deaf parents. They use sign language and often emphatically see themselves as not disabled, but rather as members of a cultural or language minority. Members of this group use deaf as a label of cultural identity much more than as an expression of hearing status. When the word is used in this way, it is often capitalized.

Deafness is not limited to humans, it can also occur in animals.