(from CYEAGER@MURRAY.FORDHAM.EDU to Primate-Talk, 2/95)

Having worked with the chimpanzees: Washoe, Moja, and Nim, and the orangutans: 
Chantek and Princess (6/79-8/81) I can attest to the following:
1. they can communicate spontaneously their concrete wants
2. they will initiate communication
O'Sullivan, C. and Yeager, C.P.  (1989). Communicative context and linguistic 
competence:  The effect of social setting  on a chimpanzee's conversational 
skill.  In R.A. Gardener, B.T. Gardener and T. Cantfort (Eds).  Teaching Sign 
Language  to Chimpanzees.  SUNY Press:  Albany, N.Y.  

1) unlike human children, they almost never comment on their environment
2) they do not ask why questions
3) both chimpanzees and orangutans make nonsense combinations of signs

This area of research has its merit, however, there are methodological 
problems (many of the same problems are also encountered in working with human 
children): the phenomenon of "rich interpretation" (overinterpreting a 
statement), anthropomorphism, human bias, and observer effects (such as 
inadvertently shaping signs by responding to approximations).  
It is remarkable that the chimps and orangutans can communicate effectively in 
another species language.  The animals I worked with had the approximate 
language level of 1 1/2 year old children. However, they never communicated 
their innermost private secrets or made predictions concerning the 
future. They did communicate emotional states, but not through sign -they 
made fear grimaces, inhibited bites or closed their eyes if they did not 
want to sign.  
Exaggerated claims concerning abilities do the animals and science a disservice.

C. Yeager