Glen Gordon wrote:
<<Perhaps the neolithic population was temporarily overtaken by IE-speaking
nomadic people (say, by 4500 BCE),...>>
About 4500BC, those "nomads" were already "neolithic" and that may be why
they spoke IE.
Glen Gordon wrote:
<<Then, because they now covered a large area thanks to their previous
nomadism, the Indo-European languages became increasingly popular well into
Europe.>>
The LBK farmer/herders of 5500BC covered and populated a good chunk of Europe
from the western Ukraine to Holland and Germany in a few hundred years, so
being a "nomad" was hardly necessary. And if they spoke an IE language or
some precursor they got there well before your nomads.
Steve Long