It remains a mystery how Pama–Nyungan, the world’s largest hunter-gatherer language family, came to dominate the Australian continent. Some argue that social or technological advantages allowed rapid language replacement from the Gulf Plains region during the mid-Holocene. Others have proposed expansions from refugia linked to climatic changes after the last ice age or, more controversially, during the initial colonization of Australia. Here, we combine basic vocabulary data from 306 Pama–Nyungan languages with Bayesian phylogeographic methods to explicitly model the expansion of the family across Australia and test between these origin scenarios. We find strong and robust support for a Pama–Nyungan origin in the Gulf Plains region during the mid-Holocene, implying rapid replacement of non-Pama–Nyungan languages. Concomitant changes in the archaeological record, together with a lack of strong genetic evidence for Holocene population expansion, suggests that Pama–Nyungan languages were carried as part of an expanding package of cultural innovations that probably facilitated the absorption and assimilation of existing hunter-gatherer groups.Remco R. Bouckaert, Claire Bowern & Quentin D. Atkinson "The origin and expansion of Pama–Nyungan languages across Australia" Nature Ecology & Evolution (March 12, 2018).
Skepticism is in order because New Zealander Quentin D. Atkinson has a history of relying on math that fails to honor existing linguistic knowledge resulting in clearly wrong predictions. But, his hypothesis here is, at least, strongly conventional wisdom confirming.
My strong suspicion is that the key cultural innovation was the integration of the Dingo into Australian society after ca. 50,000-60,000 previous years without dogs. The epicenter of this expansion coincides perfectly with the expected location of an introduction of the Dingo into Australia, and the Dingo is also known to have resulted in a second wave of mass extinctions of local fauna in Australia.