Almost twenty years ago I reviewed the "ape-language" literature in Limber (1977). I have included the abstract of that paper below. Currently I am trying to understand what the fuss is about Kanzi but at present I see no reason to change my assessment of these issues despite what has been claimed. Indeed, I am far more impressed--relative to brain size-- by Alex the parrot (e.g. Pepperberg, 1993). (I was also similarly impressed by "Fellow" the dog mentioned in Warden & Warren, 1928).
I would also add that much of the anti-Cartesian chitchat is simply uninformed or perhaps just a romantic expression of legitimate concern for preserving our primate "cousins." Finally there are some issues about evolution and the use of the expression "human language" that deserve clarification. Steve Pinker takes up some of this in his Language Instinct; also see my papers. regards, John Limber ABSTRACT: Recent successes teaching chimpanzees to engage in symbolic communication have again brought into question the Cartesian supposition that language is uniquely possessed by homo Sapiens. Despite the very remarkable achievements of Washoe and Sarah, an objective comparison of these chimps' linguistic performances with those of a typical 3-year-old child provides scant evidence for rejecting Descartes' view. An organism uses human language if and only if it uses structures characteristic of those languages. The ability of apes or even 2-year-olds to communicate and use simple names is not sufficient reason to attribute the use of human language to them. The creative or projective aspect of human language cannot be overlooked. Efforts to explain the language of deficits of apes in terms of impoverished language experience, anatomical deficits, or cognitive- structure differences are not convincing. Limber, J. (1977). Language in child and chimp? _American Psychologist_, _32_, 280-295 (Reprinted in Sebeok, T. & Sebeok, J. (Eds.) (1980). _Speaking of Apes_ (pp.197-218). New York: Plenum Press.). Also see: Limber, J. (1978). Goodbye Behaviorism! _The Behavioral and Brain Sciences_, _4_, 535-536. Limber, J. (1982). What can chimps tell us about the origins of language. In S. Kuczaj (Ed.), _Language Development: Volume 2_ (pp. 429-446). Hillsdale, NJ: L. E. Erlbaum. Pepperberg, I. M. (1993). Cognition and communication in an African grey parrot (Psittacus erithacus): Studies on a nonhuman, nonprimate, nonmammalian subject. In H. L. Roitblatt, L. M. Herman, & P. E. Nachtigall (Ed.), _Language and communication: Comparative perspectives_ (pp. 221-248). Hillsdale, NJ: Lawrence Erlbaum Associates. Pinker, S. (1994). The language instinct. New York: William Morrow and Company. Warden, C. J., & Warner, L. H. (1928). The sensory capabilities and intelligence of dogs with a report on the ability of the noted dog "Fellow" to respond to verbal stimuli. _Quarterly Review of Biology_, _3_, 1-28.