Aspects of the short analysis of Louisa, a multilingual 7-year-old girl, were described in this paper to illustrate different modes of communication between patient and analyst and the ways these contributed to shared verbalizations and interpretations. A detailed description of specific techniques showed how the development of two verbal conventions, "saying the opposite" and using foreign languages, allowed for the creation of a particular form of communication, applicable only to Louisa's treatment, and exclusive for the patient and the therapist to the relationship with each other. The suggestion is made that this creation of a treatment-specific language is an essential element of any analytic relationship and constitutes a common feature of child and adult psychoanalysis.