3. Process according to claim 2, characterized in that the models of dialogue are selected by weighting the syntax arcs between the words, the weighting taking into account, apart from the environmental noise, one at least of the following factors: the state of sensors of physical quantities relating to the surrounding conditions, the history of the dialogues, the content of a dictionary of acoustic references, the modelling of the dialogue and of the task to which the dialogues relate, the acoustico-phonetic decoding which carries out a first rejection on the basis of phonetic criteria, the various phrases already recognized.
2. Process according to claim 1, characterized in that the models of dialogue are selected on the basis of the operational context of the recognition.