Washoe and three other chimpanzees (Tatu, Dar, and Moja) were raised as if they were deaf human children and acquired American Sign Language. The chimpanzees regularly use the hand signals to communicate with each other and humans. Loulis is the only chimpanzee in the family who was not cross-fostered (he wasn't raised by humans but rather Washoe and the other chimpanzees).
After eight days with Washoe, Loulis learned his first sign. For the first five years of his life, Loulis's human handlers only used seven signs around him (the signs used were who, which, want, where, name, that, and sign). Loulis was able to acquire what he learned of ASL from Washoe.
The details of this research can be found in Teaching Sign Language to Chimpanzees edited by Allen and Beatrix Gardner.
^a Sign-language names reflect the region of origin. Natural sign languages are not related to the spoken language used in the same region. For example, French Sign Language originated in France, but is not related to French. Conversely, ASL and BSL both originated in English-speaking countries but are not related to each other; ASL however is related to French Sign Language.
^b Denotes the number (if known) of languages within the family. No further information is given on these languages.
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