Fate of Conventional PIE's Relatives (was: Stacking up on standard w

--- In cybalist@yahoogroups.com, "Tavi" <oalexandre@...> wrote:

> And finally, one of these paleo-dialects
> underwent a rapid expansion in the Chalcolithic and the Bronze Age,
> becoming a superstrate to the other varieties.

What sort of evidence persuades you that it was a superstrate, rather than the other varieties becoming substrates?

Richard.