I stumbled across a recent BBC story which discusses a pair of new papers which has found powerful evidence that Campbell's monkeys use syntax. Though their system is simple, they deliberately arrange sounds which modify the meaning of other vocalizations.
Many primatologists rightfully complain about how linguists are constantly shifting the tables against them. When Nim Chimpsky learned the meaning of words but couldn't arrange them together to form meaningful sentences, the results were dismissed. It was also argued that Nim was a poor experimental subject because of his unnatural upbringing and artificial environment. Many linguists appear to wish that language remain an exclusively human attribute, and certain aspects of language unquestionably are. But just where lays the line?
Since researchers have found non-human primates who make use of vocalizations as if they were suffixes (and mere monkeys, as well), primatologists are a step closer to determining precisely what linguistic capabilities other primates possess. This is a pretty neat little finding, and raises questions about how the potential development of language. Campbell's monkeys are far from great apes, so if they do possess stronger language functions than great apes, what does that say about the evolution of language in primate species?
This research was conducted by Klaus Zuberbuehler of St. Andrews and colleagues, and you can read the actual articles here and here. I also like how this stuff is getting published in PLoS ONE. The more legitimacy that journal accumulates, the better.
Be sure to check out the actual vocalizations and their variants on the BBC site.