Final answer:
Chimpanzees and gorillas, along with other great apes such as bonobos, have been successfully taught American Sign Language and other symbolic systems in controlled conditions. Studies have documented their ability to use sign language and lexigrams, showcasing their potential for basic language generation, which is fundamental to understanding the continuities in communicative abilities between humans and nonhuman primates.
Step-by-step explanation:
Chimpanzees and gorillas can indeed be taught American Sign Language (ASL) in controlled or laboratory conditions, as evidenced by several studies conducted by researchers and primatologists. Koko the gorilla, taught by Dr. Penny Patterson, demonstrated the capacity to learn and use about a thousand signs akin to the vocabulary of a three-year-old child. However, the interpretation and analysis of Koko's sign language use, including the ability to comment, joke, and lie, remain controversial among researchers.
Moreover, other great apes such as bonobos have also shown the ability to learn and use symbolic systems to achieve goals. Studies conducted on bonobos like Kanzi and Panbanisha by primatologist Sue Savage-Rumbaugh utilized computer-based language programs with lexigrams. These studies found that bonobos could comprehend and respond to human speech, as well as generate language, thereby exhibiting advanced cognitive skills.
These research endeavors highlight the basic capacity of great apes to generate some form of protolanguage, which refers to a simple set of gestures or utterances that may have preceded the development of human language. Still, it raises the question of whether apes display these abilities due to some innate capacity or because we have taught them symbolic systems. It also opens a gateway to understanding the continuities between human and nonhuman primates in terms of communicative abilities.