Can anyone give me a source which traces the roots of the languages spoken in the Middle East back from 5,000 to 600 BCE or thereabouts?

What I am looking for is essentially a Semitic langauge family tree that will outline changes to the languages over different regions over time.

Thanks.

Also, what is the oldest Semitic language to have been written on tapa?
Do we have any examples of Akkadian on tapa, or just on clay?

Just guessing, One Raven, but I'd say Sumerian was the oldest Semitic language, and probably the oldest writing system (on clay, so far as I know).