During the 1920s-30s, Lev. S. Vygotskij (1896-1934) is interested by the semiotic mediations of mental life in order to study the development of the psychic, emotional and physical functions of the child. Straddling pedology and defectology, passionate about art, philosophy and literature, he judiciously separates mental age from school age, but also clinical knowledge from educational realities. Still topical, although still under construction during his lifetime, the vygotskian educational project insists on the dialectical character of development. If the organicist current can claim that the "little man always learns better the facts that he discovers rather than the principles that are imposed on him" (Piaget, 1997), it is quite different for those who advocate the vygotskian cultural-historical approach. In this article, we show that interventions and learning vary historically according to epistemological orientations, contexts, but also the methods recommended to regularize and to "perform" in historically constructed frameworks (signifiers). At school and in families, it is impossible to escape the obligation to favor experiences based on cultural mediations, both linguistic and historical. Like Vygotskij, we believe that the “significant actors” must privilege the pedagogical diagnosis with the help of skillfully orchestrated interventions around the near development zone (ZDP).