Sorry that my inquiry was seen by you as playful.  I hadn't meant it to be.  The point I was making was simply that written evidence doesn't stretch back to the times of the origins of language no matter whether you divide them into three:     1. The ultimate origins of human language;    2. The origins of all human languages;    3. The origins of Nostratic languages -- or not.  Without written documentation, origins becomes nothing more than conjecture.
 
As far as Proto-World -- that sounds like a decent handle.  IMO it should be able to encapsulate all the groups that Nostratic left out.  However, and I repeat for the zillionth time, Alekseev always said that all languages from the beginnings of time were mixed.  Thus, even Proto-World has a problem in reconstruction.
 
Gerry