The purpose of the present study was to train different verbal classes in a 44-year-old woman to reduce aberrant verbal behavior. She had been hospitalized for 22 years in different psychiatric institutions, and has been diagnosed with schizophrenia, developmental disabilities, non-organic psychosis, and autism. Assessment of her verbal behavior showed that a small amount was adequate verbal behavior, whereas almost the entire repertoire of verbal behavior could be characterized as aberrant verbal behavior ('psychotic' and repetitive verbal behavior), and this behavior was maintained by social reinforcement such as smiles, various comments from other persons. The treatment program was based on results from the assessment results and was focused on establishing relationships between a variety of verbal response responses and proper controlling variables. She was trained to produce different verbal classes, mainly mand, tact, intraverbal, textual, transcription, and dictation responses. The duration of aberrant verbal behavior and the rate of 'psychotic' verbal behavior were gradually reduced as a function of an increasing number of adequate verbal responses. In the study, we present data covering a very long period; the last data point was acquired 25 months after the start of the program.