Kanzi 2.5 years + Mulika (Pygmy chimps)
Austin + Sherman (Common chimps)
Kanzi and Mulika were exposed to using the lexigram when their mother was trying to be taught.
Tests of language: Spontaneous use 9/10 times. Formal lab tests- Photo to lexigram. Spoken to photo.
Results: Kanzi acquired 47 words and produced 2540 combinations of words. 80% of combinations made were spontaneous.
Conclusions: Non-humans have linguistic abilities similar to humans. It is difficult to generalize as only 4 chimps were studied