An experiment with 17 teachers of first-year high school French recruited from the staffs of three large, diversified San Jose, California school districts was designed to (1) observe closely the classroom behaviors of the participating teachers, (2) identify those successful in terms of pupil achievement, and (3) compare the behaviors and characteristics of these teachers with those identified as less successful. The predominant feature of the research was the systematic observation and rating of the classroom behavior of the teachers by recording four 15-minute class segments over a period of five months. By means of specially constructed criterion tests, student and teacher questionnaires, the Modern Language Association Proficiency Tests for Teachers, and the observation of classroom procedures, data were gathered that yielded 40 variables. An analysis of the intercorrelation matrix of the 40 variables showed that a series of interrelated teacher behaviors and characteristics correlated significantly with student achievement. The two research hypotheses formulated focused on the linguistically definable and pedagogical aspects of the teachers's classroom behavior. The major recommendations emerging from the study concerned teacher training innovations and further research needs. (Author/AF)