Research was conducted to investigate the development of linguistic competence in early French immersion programs. Fifty-five students in grades 3, 4, and 5 were administered a test of oral production in French. Twenty-seven grammatical features were examined by means of a detailed error analysis. The results show that there was little improvement in performance from grade 3 to grade 5, and the features that were mastered at the end of grade 5 were either "unmarked" or invariant forms. The results were then compared to those previously obtained for grades 1 and 2. The comparison shows that competence in the second language improves from first to third grade and then remains stable from grade 3 to grade 5. Possible reasons for these findings are discussed in terms of intensity of instruction at each grade level, and the basic approach to second language teaching in immersion programs. Suggestions are made for the integration of second language teaching into the teaching of content subjects. (Author)