There is a very interesting article in today’s NY Times on the Demotic dictionary project. The dictionary, which a quote in the article calls the Demotic equivalent of the OED, is nearing completion after 40 years of work. Demotic is the Eqyptian everyday language that with heiroglyphics and Greek was on the Rosetta Stone. It was in use for a thousand years until 500 A.D. and then was displaced by Coptic and Arabic.
The article explains that some words in modern english such as “adobe” and “ebony” originate from Demotic through Arabic.