Final answer:
Apes in language experiments demonstrate the use of symbolic systems and the capacity for a simple form of language, though this differs fundamentally from the complexity of human language. The development of tools by early hominins and associated cognitive and social abilities are thought to be closely linked with the origins of human language.
Step-by-step explanation:
The features that apes demonstrate in experiments on language include the use of gestures or tokens to refer to objects, the combination of these signs in a rule-based manner for communication, and the capacity to develop a form of protolanguage. These features suggest an inherent ability to adopt some basic aspects of human languages, illustrating that apes can use symbolic systems in cooperative interactions to achieve specific goals. Studies of apes like Koko have shown that, while their communication systems are unlike the infinitely creative and flexible nature of human language, they can still master a basic vocabulary and use words and combinations to express desires, indicating the presence of certain biological prerequisites for language learning. Regardless, the full-fledged language capabilities seen in humans have not been replicated in apes, marking a significant distinction between human and nonhuman primates when it comes to language complexity.
Evidence from our hominin ancestors also plays a crucial role in understanding the emergence of language. Material culture, such as the development of stone tool technologies by hominins like Homo habilis and Homo erectus, required complex social and cognitive abilities, which are also important for language. The evolution of these abilities was likely entwined with the emergence of language, suggesting a reciprocal relationship between tool use, brain development, and language capabilities.