Denken Und Sprechen by Lev Semyonovich Vygotsky

A seminal account of how language and thought are intertwined, arguing that higher mental functions arise through social interaction and the gradual internalization of linguistic and cultural tools; it traces the transformation from external, social speech to private speech and finally to inner speech as a mediational mechanism for cognition. The work distinguishes between spontaneous and scientific concepts, explains how signs and cultural artifacts shape mental processes, and situates cognitive development as a historically and socially mediated process. It emphasizes internalization, semiotic mediation, and the educational implications of viewing cognition as fundamentally social rather than purely individual.