Piotr wrote
> What Australia and PNG have in common is the genetic diversity of
their languages. Languages are more numerous and families tend to be
slightly bigger in PNG (Austronesian, of course, is a case apart);
there is probably more creolisation as well (as opposed to mere
diffusion). Anyway, whatever the local conditions, old and relatively
undisturbed linguistic areas tend to be occupied by many tiny
families and linguistic isolates, and the construction of large-scale
family trees for them proves difficult or impossible.
This is not really true. What is required however, is a very
intimate detailled knowledge of a large number of local languages. I
was able to follow "trees" linking Enga, Huli, Angal Heneng, Kewa,
Samberigi and Wiru languages in the Southern and Western Highlands
(Central West Highlands Family of the Trans Papuan Phylum of Stephen
Wurm), and Bosavi, Biami, Foi'i and Fasu languages of the Western
Family of the same Phylum, in 1980-83.
Your explanation of "micro-explosions" is very real, however, and
seems to have been linked with the introduction of waves of new
cultivars and the effective exploitation of these. The first one
mentioned above seems to have been due to the origins of new cold
resistent crops in the Enga Region of the Papua New Guinean highlands.
The extent of the Trans Papua Phylum (and to related interior
languages in New Britain, New Ireland, and elsewhere) seems due to a
very early expansion of agriculture, extending outwards from New
Guinea into the Solomon Islands to the East and into Timor and
Halmahera to the west. This seems parallel (and even earlier) to the
Middle Eastern Explosion associated with post glacial grain
production.
Regards
John