Location does make a difference. There is no such thing as a worldwide deaf community. Each deaf community is influenced by the culture of its location. Deaf people in the USA have different experiences from deaf people in other countries. Available education, social services, laws, technology, etc., are all very different influences. All those factors do influence communication between the deaf and hearing. Just the fact that Americans say, "deaf," and some other countries still use the phrases "deaf and dumb" or "deaf-mute" puts a different face on initiating communication between the deaf and hearing groups.
I hope your dissertation doesn't lump all deaf people together.
You find some commonalities amongst deaf people across national boundaries but there is also much diversity. I don't know how you'll manage with such a small sampling.
Even within the USA the life experiences of poor Southern rural black deaf people are very different from middle class Northern urban white deaf people.
There are sooooooo many variables to consider.
I hope you have enough time left to cover everything.
