Although *spoken* Chinese has obviously varied (the written language
is the same across China, but IIRC, there are mulitple, mutually
unintelligble spoken "dialects").
Hmmm... Hebrew has been preserved in large measure because there are
texts in the language which were preserved largely unaltered, and
which were of interest to a population with citicial mass (although
Hebrew was, for quite a few centuries, of mainly liturgical interest,
and not much used in daily life). Are there any texts which played a
similar role for the other languages, or are there other
preservationist forces at work?