>If anyone knows of a well-documented case of an absolute
> innovation that saw its first light and immediately exploded to
> encompass an entire language within a generation or two it would be
> very interesting to hear about it.
Watch English English for the next few years. People under a certain age in
most of England already say /?/ for <t>. This is (a) a recent change (b) a
rapid change (c) a community-wide change.
It would be an irrelevant quibble to say that English English is not an
"entire language". It will still serve as an example, of the kind you
request.
I accept it is not an "absolute innovation" since this pronunciation was
limited to a few social marked dialects for years. It is the speed of the
recent spread of the change, and its loss of social marking, which is so
enlightening.
Peter