ABSTRACT
This chapter presents the science behind supposed sign language in nonhuman primates. Several chimpanzees, bonobos, or gorillas have been claimed to have the ability to use various types of sign language to communicate. This has been used to imply that the linguistic ability of humans is more widespread than just our species. However, the facts behind these case studies do not support this assessment. While the animals in question to have significant abilities, cognitive and personal biases on the parts of researchers have led to a general exaggeration of their language skills, bordering on linguistic pseudoscience.
