Science and Speech in Determining "Human" Kind

It's naive asking for "proof" of something in ancient history. What you should ask for is evidence. Imagine me asking you for proof that speech did not exist before 6000 years ago. Here's some evidence for you, related to the hominid evolution of the refined hearing necessary for complex speech.As for our own species, there's plenty of evidence that they were doing agriculture and extensive trading more than six thousand years ago, and don't you think this would be difficult without complex speech?I could find some more evidence, but first, perhaps, you could show some evidence (not proof) that speech began around 6000 years ago.The beginning of written language isn't any good, as we know of many human cultures which have spoken language, but no written language, meaning that spoken language clearly can exist without a written form.

You're not actually talking about speech, you're talking about written language. I'm writing now, but I'm not speaking. No one requires written language in order to speak. Children speak long before they read and write.Written language is a technological tool. Many known cultures with complex spoken languages do not use written language. Implying that the earliest written languages have anything to do with the first human speech is like saying humans could not move around before they had invented the wheel, or could not farm before they had invented the tractor.Chimps can cry "hey, food here" and "hey, good food here" to each other. Because you can't speak Chimpish, like you can't speak Chinese, doesn't mean they can't understand things from each other's cries. Some experts reckon them to have the verbal communication equivalent of 100 words.For our species, complex speech is an inbuilt biological thing, and bear in mind that skulls like yours and mine have been found that have been dated at more than 150,000 years old.Like us, these people had a well developed "Broca's Area".Broca's area - WikipediaThey certainly spoke to each other, without writing. Just as certainly as they moved around without wheels.