Chimpanzee Studies

Scientists have long been fascinated with the studies of language, as it was potentially the most uniquely human cognitive ability. To test the hypothesis of the human-uniqueness of language, scientists have attempted to teach several species of great apes language. One early attempt was performed by Allen and Beatrice Gardner in the 1960s, in which they spent 51 months attempting to teach a chimpanzee named Washoe American Sign Language. Washoe learned 151 signs in those 51 months.[ Over a longer period of time, Washoe learned over 800 signs. However, there is still debate among some scientists about the great apes' ability to learn language.

Source: Wikipedia