"ScienceNOW.org", Science, vol. 326, 11 December 2009, p. 1467:
An Introduction to Monkey Grammar?
It's not quite Shakespearean word play, but a species of African monkey can modify individual warning calls to produce novel meanings, according to new research. And because the wild monkeys tack the same sound onto the end of their calls, the authors speculate that they could resemble suffixes. But it's debatable whether the sounds serve a grammatical purpose like that in human language. http://bit.ly/monkeygrammar
Chomsky's assumption, that the semantic central in humans, that generates grammatical linguistic structure, is unique to humans, is an undarwinian conceit. Granting that human language abilities required dramatic genetic mutations, forebrain development, and structural changes in human vocalization anatomy, granting that todays higher primates do not have all of these necessary structures and processes for true human language, and granting that neither the ancestors of humans or primate had such structures, it nonetheless contradicts the process of evolution, genetic change, and natural selection, that underlay all biology, to think that higher primates and our ancestors possessed none of these capabilities.
There has, on Darwinian principles, to be a continuum between the ancestors of humans and primates and between humans and primates today that diminishes the leap between primate vocalization and human language. The discovery that monkeys have standard atoms of vocalization they can attach to calls to inflect them and that they can assign new meanings to calls on the basis of inflections indicates that the discovery of rudimentary grammatical operations is not far away.