Final answer:
Gorillas cannot speak like humans due to the lack of a specialized vocal tract and the cognitive structures required for human-like speech. While primates such as Koko the gorilla can learn basic sign language, their communication systems do not match the complexity and flexibility of human language.
Step-by-step explanation:
Why Can't Gorillas Speak Like Humans?
Gorillas can't speak like humans primarily because they lack the specialized vocal tract that humans have, which is necessary for articulating the wide range of sounds that make up human speech. Moreover, the communication systems of gorillas and other primates are vastly different from human language. While primates such as chimpanzees and gorillas can produce a variety of calls and may learn to use gestures or symbols to communicate with humans, their natural vocalizations are relatively fixed and not as flexible or complex as human language. The anatomy of the gorilla vocal tract and the absence of necessary cognitive structures prevent them from speaking like humans. Research shows that primates have their own ways of communication. For instance, chimpanzees use a variety of vocalizations, and the duets of gibbons convey specific information, but these are limited compared to the infinite productivity of human language. Despite some great apes being taught to use gestures or tokens to communicate, and even being capable of learning a basic form of language (protolanguage), their abilities are not akin to the open-ended and highly syntactical structure of human language. One famous example is Koko the gorilla, who was taught sign language and was reported to have learned about a thousand signs, equivalent to the vocabulary of a three-year-old child. However, the claims about Koko's ability to use language inventively and with intention, like humans, are disputed, and largely based on the interpretation of her trainer. In summary, while primates can communicate and learn certain aspects of language, the complexity and infinite flexibility of human language that arise from sophisticated cognitive abilities and a specialized vocal anatomy are unique to humans.