> Ironically, I think it's precisely a lack of _equilibrium_ which has
> likely created the Australian situation. As Dixon himself notes on
> 92 of the "Rise and Fall", Australian prehistory has seen several
> cycles of population contraction (extremely dry periods) followed by
> expansion (wetter periods) and contraction again. Language mixing
> have taken place when the remnant population was confined to
> relatively few spots along the coast and major rivers. Repeat
> times and stir well, and you may get something like the Australian
> linguistical situation. This did not happen in the climatically
> more stable New Guinea, or in places where there was a constant
> of new populations and languages.
The current archaeology shows that in only one case, during the arid
phase of the lacal Maximum 18,000 BCE did the cycles of dry and wet
over the entire continent coincide. The expansion of dune fields
over the greater part of the continent saw probably saw an overall
decline in Abroiginal populations and the loss of some outlying areas
(eg the Karta tradition on Kangaroo Island etc). It is interesting
that this same period saw the extinction of most groups of magafauna.
Studies of Australian prehistory also show the exstence of certain
imassable areas (usually deserts) linked by corridors. Cultural
traditions, trade routes and presumably linguistic influences
traveeled down the corridors to meet and mingle in the more
gavourable "node" areas. It is interesting that this closely
approximates to Aboriginal conceptions of the continent too, based on
routes of "song lines", with nodal "cross over points" where stories
meet and mingle.
I feel the difference between Australia and New Guinea is in part
linked to the fact that the deserts appeared to be only a minor
barrier, trade routes were longer and movement of peoples from one
side to the other side of the continent (travelling along well known
songlines), at least in the Pama Nyungarn territory, was not
uncommon. None of these conditions applied in the area of Papua New
Guinea. Trade routes were shorter and the country much more
imapssable than Australia.
These conditions also apply in Western Europe and Eurasia for Indo-
European. The Steppes and northern plains tend to be the areas where
single large cultural/linguistic groups tend to come to predominate.
Mountainous and forested areas tend to be characterised by smaller
locally based groups, less mobility and trade routes being shorter as