Language as Home and Language as Exile

this should be part of theoretical framework of a doctoral thesis titled as” the representation of Arab American fiction: RIHANI, HALABY AND SHADID”.

You have to work on the theoretical frame. And for that, your major points, of those that you indicate in your general index, would be

1-Identity Social, cultural Issues Faced in Exile
2-Language and Identity of the Immigrants in Exile
3-Language as Home
4-Language as Exile

This is enough for the theoretical framework for the diss. Though you had the last two point as just one, I think you can split them in two, talking about the role of language as a home in one section, and then the role of language as exile, in a different section.
I suggest that you begin with this last part of the theory, because I think you will find more information, and you have already done part of the research for the writing of the chapters you have worked on.

So now it is a matter of going to the databases in search of relevant theory discussing language as home, a home in language, and then the role of language in exile.