Fountain of Knowledge

I don't know anything about Syria in 4,000 BC. However, I think thee's and thou's are a part of King James English. I don't think English had come into being until after the Medieval era. It is a member of the Indo-European family of languages that came mostly from Low German.

I would begin by finding out what language was spoken. But, being that you are going back 6,000 years, it might be best to write the dialogue in modern English, avoiding any modern terms--assuming that you are writing this story in English. I don't know what to advise you about contractions.

Light
Science, Science Fiction/Fantasy, Metaphysical