Peg writes... i certainly think that written language is unique to todays humans...i've never been presented with anything different...and as i've already stated, written language has only been around for the last 5,000 odd years... unless you can present anything different on this???
Peg, your definition of written language is as weasily as the word "kind"; there is no hard line between proto-languages using ideographic image-symbols and scripts indicating more complex capability. Proto-languages are in evidence in the 7th millennium BCE and their use flows smoothly into written language.
At what point have you identified a time and place where the pre-human hominids died out and the modern humans begin? How does that point compare to the actual evidence that shows continuous development of written language from crude drawings through to e-mail and text-messaging. If Adam and Eve were created with the capabilities to write and no others then we should see all proto-languages die (at about the same time I assume) and all real languages evolve from a single, fully formed, written language (presumably Hebrew). Please direct us to a study of early writing that shows this relationship.
I know you'll fall back on the Tower of Babel to further confuse the issue, but please do give us some dates along with links showing your evidence. Please show me why everything I've learned is wrong and why you are right.