A greater understanding of psychological treatment can be achieved through an analysis of the language used by those participating in such treatment. Several conceptual aids are needed: (1) a theory about how language conveys meaning; (2) a model of language in psychological treatment; (3) reliable units of measure; and (4) since psychological treatment consists of thousands of words, a relatively rapid method of processing language. The language model of the psychological treatment process uses linguistic displays, the observable exchange of signals, an inferential process of attributing meaning to those signals, and observable outcomes by which to judge the attempted social influence. The Matrix Model of Case Grammar is used to empirically test the language model in observable units of measure by classifying the structures of natural language according to semantic relationships and stylistic properties. The Computer-Assisted Language Analysis System (CALAS) assists in testing the conceptualizations and in implementing the case grammar paradigm. This technological tool allows reliable and rapid analysis of the natural language of counselor and client across different theoretical approaches to psychological treatment. Semantic and stylistic attributes of language which convey meaning beyond their literal grammatical components (e.g., intentionality, influence) can be used to test hypotheses related to psychological treatment. (BH)