The concept of "Deaf culture" has been around for a very long time but this term "Deaf culture" doesn't emerge until the 1970s. Before that, the conceptual terms were used, such as DEAF WAY/POSS, DEAF WORLD, DEAF TEND-pa. Likewise for 'hearing culture' but that's another story.
"I had now to see them [Deaf people] in a new, 'ethnic light,' as people with a distinctive language, sensibility, and culture of their own." -- Oliver Sacks, Seeing Voices.
What is culture? There are over 100 definitions! Basically, culture is a set of learned behaviors of a group of people who have their own language, values, rules of behavior, and traditions.
"We believe that you cannot teach a new language if you do not teach the culture behind that language." -- Gabriela Mistral Latin American School, Edmonton.
Language and culture are inseperable. Where there is a language of its own, there is a culture and heritage. Deaf people are a cultural-lingual group. Deaf people usually don't see ourselves as a disability group which is a social construction in the hearing world.
"Deaf culture is the set of social beliefs, behaviors, art, literary traditions, history, values, and shared institutions of communities that are influenced by deafness and which use sign languages as the main means of communication." -- Wikipedia.
There are three general aspects of culture: materialistic, normative, cognitive. Or Nitza Hidalgo's three levels of culture: concrete, behavioral, and symbolic.
Materialistic aspect is something people can observe concrete things of a culture.
For example, in Deaf culture, one can see concrete signs such as teletypewriters (TTYs), texting, flashing light for doorbell and phone ring, etc. And, most of all, signing.
Normative aspect of culture is a set of rules of social interaction that outsiders can observe behaviors, such as rules of touching, eye contact, a way of introducing, attention-getting, pointing, etc.
Cognitive aspect is something one cannot observe, such as thoughts, attitudes, beliefs, and values. They can be learned or observed through language and communication.
My ASL students, who were given a task to attend a social event in Deaf community, outlines common observations as follows:
Naturally, there are variations among Deaf people (e.g. their nationalities, personalities, etc.), but the cultural differences are relatively comparable on a large scale.