Alfred Russel Wallace was the co-discoverer of natural selection. His paper provides a framework for thinking about how culture and environment constrain varieties to stay true to type and also how changes enable varieties to stray indefinitely from the original type.
It is now well established that language
cannot follow just any old rules. Linguists a few decades back thought there
was no limit to the variety of language, but research has since identified a
number of formal constraints that mark boundaries. Language can work within
those borders, but not cross them. The trouble with those borders is
understanding what these constraints mean psychologically and neurologically.
There must be some reason beyond the formal rules for why these constraints
existed. We hardly know how to think about these matters, let alone explain
them. A letter in the most recent issue of Nature reminds me, however,
that clues are coming in from, of all places, songbirds.
clipped from: www.babelsdawn.com 