Language evolves in fits and starts In Brief (Pagel 2008)
New Scientist; 2/9/2008, Vol. 197 Issue 2642, p19-19, 1p
"An evolutionary tree connecting the major language families charts
their divergence from one mother tongue into hundreds of different
LANGUAGES evolve in fits and starts rather than gradually, an
analysis of the Bantu, Indo-European and Austronesian families of
Mark Pagel of the University of Reading, UK, and colleagues
constructed an evolutionary tree for each of these language families.
The "length" of each branch back to the root of the tree records how
different a descendant language is from its ancestral root, in terms
of how many words were replaced.
The team found that in each language family there was significantly
more lexical change along branches in which more new languages had
emerged, suggesting periods of abrupt evolution in which each new
language created a burst of words (Science, vol 319, p 588)."
posted by M. Kelkar