The aim of this paper is to highlight the importance of the Lacanian notion of “lalangue” as it allows us to consider a topology of the body for Lacanian psychoanalysis. “Lalangue” is transitive between infant and mother, the body is gestated in the transitivism and takes its trace. Body constitution is synchronous to the emergence of the unconscious. The infant is going to extract the battery of signifiers from “lalangue”. “Lalangue” is an operation and, simultaneously, a product; both are indispensable to have a voice. The comment of the case of an autistic child treated by Sami Ali will support this idea.