Deafness is the condition of not being able to hear. In the United States, deaf people are entitled to certain government programs to help them due to the limitations imposed upon them by their disability. The legal definition of deafness in America is not absolute loss of hearing, but an inability to hear up to an acceptable level even with corrective devices.
Deafness can be a condition from birth or be caused be a later accident or illness. Loud noises can cause deafness or hearing loss.
In the United States and English Canada, American Sign Language (or ASL, Ameslan) is the most used sign language. There is a common misconception that ASL is simply signed English; it is in fact a natural language (as opposed to a conlag), and is not related. For example, ASL is not mutually intelligible with British Sign Language, which is the dominant sign language of England.