Vygotsky's belief about private speech can best be summarized as:

Vygotsky believed that private speech plays a crucial role in intellectual development and adaptation. He viewed it as a cognitive tool that children use to guide their own thinking and behavior, reflecting their inner dialogue as they work through problems. This self-directed speech not only aids in problem-solving but also helps with self-regulation and the internalization of knowledge.

According to Vygotsky, private speech is particularly significant in the context of learning and development, as it allows individuals to verbalize their thought processes, manage tasks, and navigate complex situations. This underscores the idea that private speech is integral to developing higher mental functions and is essential for intellectual adaptation throughout the learning process.

In contrast, the other perspectives presented do not capture the depth of Vygotsky's belief. While private speech can facilitate social interactions, its primary role extends beyond mere social communication. Although private speech is observed in younger children, it is not limited to them; even older children and adults use self-directed speech during problem-solving. Lastly, while private speech is a verbal strategy, its focus is on internal dialogue rather than just external communication.