Great ape language

Research into great ape language has involved teaching chimpanzees, bonobos, gorillas and orangutans to communicate with humans and each other using sign language, physical tokens, lexigrams, and imitative human speech. Some primatologists argue that the use of these communication methods indicate primate "language" ability, though this depends on one's definition of language.

By that extension, contemporary animal cognition research leans toward not teaching apes human forms of communication, but rather observing apes in their inter-species communication. Additionally, earlier distinguished case studies in the research field such as Nim Chimpsky, and Koko have been criticized as having subjects produce results based on operant conditioning.

However, there is still evidence of certain apes, such as Kanzi the Bonobo, understanding crucial aspects of human language such as grammar, extensive vocabulary and reservable sentences.