Lameen Souag, the Algerian linguist at the Jabal al-Lughat blog, posts fairly rarely these days since he finished his doctorate at SOAS, got married, etc. And when he does, he often posts on African languages of the Sahara and Sahel. But when he posts on Arabic or Berber, he's usually worth referencing or outright pirating. His latest deals with the little-known but fascinating surviving languages of South Arabia. In Yemen (and Oman, where Jon Peterson did a piece on these minority languages for MEJ some years back [link coming soon]), several remnant languages descended from Old South Arabian and (if my understanding is correct) more closely related to Amharic and other Ethiopian languages than Arabic, still linger, though of course much influenced by Arabic. He cites two interesting YouTube videos, though these will only be useful if you already know Arabic. He notes both an attempt on YouTube to record all the dialects of Arabic and separate languages of Yemen:
and another which introduces some basics of the most widely spoken of the surviving South Arabian languages, Mehri, to Arabic speakers.