Commonly, the uppercase ‘Deaf’ is used when referring to a particular group of deaf people who share a language – American Sign Language (ASL) – and a culture. The members of this group have inherited their sign language, use it as a primary means of communication among themselves, and hold a set of beliefs about themselves and their connection to the larger society. This group is distinctive from those who find themselves losing their hearing because of illness, trauma or age; although these people share the condition of not hearing, they do not have access to the knowledge, beliefs, and practices that make up the culture of Deaf people.
Identification as culturally Deaf is not simply a shared camaraderie with others who have a similar physical condition, but is, like many other cultures in the traditional sense of the term, historically created and actively transmitted across generations. Deaf people have found ways to define and express themselves through their stories, performances, and everyday social encounters. The richness of their sign language affords them the possibilities of insight, invention, and irony.
(Passage taken from Deaf in America: Voices from a Culture, Carol Padden and Tom Humphries, 1988.)