Classroom dialogue is an important influence on students' learning, making the structure and content of dialogue important research variables. An analysis of two sample classroom dialogues using the Thematic and Structural Analysis (TSA) Technique shows a positive correlation between the quality of dialogue structure and the level of student achievement. The TSA Technique overcomes the inadequacies of earlier methods of analyzing classroom language by (1) studying dialogue rather than teacher monologue: (2) eliminating the need for specifically prepared transcripts; and (3) accounting for the context of words, an element left out of other computerized analyses. The steps in using TSA Technique are: (1) divide the dialogue into cycles; (2) select substantive words; (4) produce a correlation matrix; (5) factor analyze the matrix; (6) cross-correlate the factor scores with a lag of 1; and (7) draw diagrams of both the distribution and relationship of themes across cycles and among the themes themselves. (Six tables of data and 4 figures are included; 101 references are attached.) (MHC)