Concept:Lev Vygotsky believed language is essential for cognitive development, not separate from it.Explanation:Vygotsky's socio‑cultural theory states that social interaction builds cognition. Language acquisition is the main driver of cognitive growth. Children use private speech to guide themselves, turning shared knowledge into personal understanding. He outlined three stages of language:
Social speech
It refers to external communication to talk with other people.
Private speech
It refers to internal communication by which children direct themselves. It is a mechanism to turn shared knowledge into personal knowledge.
Inner speech
It arose when private speech goes underground and is transformed into silent inner speech.
Therefore, language actively facilitates cognitive development.Answer:Option C: language facilitates cognitive development.