Dear Saeed, I wish you all the best in your research. I wish I could help you but I am not very much interested in this area of research. I hope that other colleagues help you... Good Luck...
Dear Saeed, Last year I participated to a conference on Linguistics in Arabia in King Abdulaziz University in Djedda. Professor Janet Watson had a keynote address entitled The documentation and ethnolinguistic analysis of the Modern South Arabian Languages. in particular, she talked about the Arabiic dialects of Oman and mainland Yemen. I think that she is the one who can help you the most in your quest. here's her email address: J.C.E. [email protected]
My advice for you is to go to Dhofa'r ,kingdom of Oman. There it is at least peaceful peaceful and people are very helpful. You might even consider addressing the Omani kingdom of education. I worked there and I know that Omanis in general are very helpful. You do not need any outside help if you speak Arabic and Hebrew. Actually you will have all what you want..
I am not a linguist but I have used linguistic Semitologist works. I suppose my answer is not quite up to date, but you may wish to check some older literature (on the other hand the progress in Semitic linguistics is rather slow as there are very few universities in the world that still keep departments or rather chairs of Semitics. Mine (Uppsala University, Sweden) is one of them, but none of my colleagues carries on research in South Semitic languages, where MSAL, non-direct descendants of the ESA (Epigraphic South Arabian, a.k.a. Sabean, a.k.a. Sayhadic) belong. Please note that these – Mehri, Harsusi, Jibbali (older name: Shhauri), Hobyot, Soqotri, all except Mehri on the verge of extinction - should not be confused with the (North) Arabic dialects spoken in the region, as one of the respondents suggested in his answer.
In any case I would suggest that you start checking what is the state of studies in the area you are interested in from the following paper:
Simeone-Senelle, Marie-Claude, „The Modern South Arabian languages“, [in:] The Semitic languages, edited by Robert Hetzron, (Routledge Language Family Descriptions), London: Routledge, 1997, pp. 378-423;
Since you say that you are interested in Semitic linguistics in general, I add that you will find in the same book chapters/papers devoted to other Semitic languages as well as to their general classification.
You may also check:
Lipinski, Edward, Semitic languages: outline of a comparative grammar, second edition, (Orientalia Lovaniensia Analecta, 80), Leuven: Uitgeverij Peeters en Departement Oosterse Studies, 2nd ed. 2001 (1997);
and:
Semitic Linguistics: The State of the Art at the Turn of the Twenty-First Century, edited by Shlomo Izre’el, (Israel Oriental Studies, 20), Winona Lake, IN: Eisenbrauns, 2002,
I am actually working on MSAL for my PhD. If you need any help with bibliography or if you want to exchange ideas and opinions don't hesitate to contact me!