In the course of prevention network in CRIPS, the author presents a research carried out on the the language underlying the actions of communication and prevention of Aids towards young people. The aim was to analyze, amid every single act of communication the representations covering words in order to guarantee that the messages that are emitted do indeed refer to the realities and values that organize on the one hand the sociolinguistic universe of the adults and on the other, that of the youths. The question thus asked is whether the modes of expresion can be transposed one from the other.