A complete course of psychotherapy provided extensive information about natural speech patterns of a male psychiatrist and a female patient. Contrary to assertions of the deferential function of tag questions, the patient's use of this form increased as she gained in self-confidence and improved her psychological adjustment. Qualitative analysis of the type, antecedents, and consequences of tag questions in sessions at the beginning and end of the therapy shows how the patient's use of the form reflects her growing independence. Quantitative and qualitative analyses of verbal interaction offer complementary benefits, and a two-stage research method is advocated. (Psychotherapeutic discourse, tag questions, pragmatics, sociolinguistics, psychotherapy process)