A method for the analysis of a message given by an interaction device to a system of man-machine dialog includes three consecutive steps, a first step of syntactic analysis, a second step of semantic analysis and a third step of execution analysis. The syntactic analysis assesses the conformity of a message given by the interaction device with a predefined form of dialog, the semantic analysis assesses the meaning of the request made by the operator engaging in dialog with the machine, and the execution analysis determines the performance of an action to be undertaken coming from the step of semantic analysis. The invention finds particular application in systems of man-machine dialog having many kinds of interaction such as speech, gesture, and expressions.