The longest and most intense attempt to teach human speech to a chimpanzee was conducted by Keith and Cathy Hayes between 1947 and 1954.  Their chimpanzee, Viki, was raised in an enriched environment that they hoped would stimulate language acquisition.  Although Vicki only managed to produce four voiceless approximations of words: mama, papa, cup and up, (1) it was noted that she linked gestures to her communication attempts and also used gestures by themselves to communicate. (2)
 

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Viki loved just monkeying around
 
 
 
 

Ape Communication Studies Main Chimpanzee page Animal Communication Page

(1) Progress in Ape Research pg. 78, An introduction to Language pg. 402
(2) Progress in Ape Research pg. 78