If I'm reading Wikipedias article on glacial periods correctly it indicates that the last time sea levels lowered significantly would have been between 71k and 115k years ago. I wonder if language complex enough to have an oral tradition existed that far back.
Relative sea levels can change because the land is rising as well as sea levels dropping - post glacial rebound means that areas that were heavily glaciated can actually be lifting at quite a rate:
e.g. Here in Scotland you just have to look at a shoreline to see that relative sea levels have dropped quite a bit even though sea levels have risen. When I was a kid I can remember my father talking about legends of Vikings sailing round Roseisle in Moray - which is quite high and dry now.
Very likely. You may be interested in https://en.wikipedia.org/wiki/Origin_of_language ("The results suggest that language first evolved around 350,000-150,000 years ago, which is around the time when modern Homo sapiens evolved") an https://en.wikipedia.org/wiki/Behavioral_modernity ("Howiesons Poort, Blombos, and other South African archaeological sites, for example, show evidence of marine resource acquisition, trade, and abstract ornamentation at least by 80,000 years ago.")
Nope, more like 12-8k years ago. Check out the Holocene sea level rise [1]. Jeffrey Rose's Persian Gulf Oasis / Out of Arabia theory is especially intriguing.
Aboriginal people wouldn't be in Australia at all if it weren't for sea level lowering, so you could say it's actually more dramatic than flooding.
"There is considerable discussion among archeologists as to the route taken by the first migrants to Australia, widely taken to be ancestors of the modern Aborigines. Migration took place during the closing stages of the Pleistocene, when sea levels were much lower than they are today."[1]
"It is generally believed that Aboriginal people are the descendants of a single migration into the continent, a people that split from the first modern human populations to leave Africa 64,000 to 75,000 years ago, although a minority propose that there were three waves of migration, most likely island hopping by boat during periods of low sea levels"[2]
Since we are land animals, a lowering of the sea would provide more grounds to be covered by humans; more space means less interaction and less conflict.
Maybe the sense of wonderment in finding new grounds is not enough to be folk-told throughout generations. As in the news, we tend to stick to the bad news rather than the good ones.