A project was designed to help mainstream teachers in Grades 1-3 facilitate language learning in all students, but especially in those who have language disorders. A naturalistic study followed teachers participating in the project to examine what factors promote change in teachers' knowledge, beliefs, and practice. The overall approach to language arts learning and teaching fostered by the project was a constructivist one resembling the whole-language approach. Three elementary schools in Eastern Massachusetts, and a set of 10 teachers underwent intensive training and were studied over a 3-year period. Results documented the changes teachers made with respect to the organization and climate of the classroom (finding some of the most consistent changes here), and to reading and writing instruction. Results further depicted, in mini case studies, the way each teacher changed over the 3-year period. In addition, results identified three sets of factors (teacher, intervention, and contextual) that had an impact on the change process. Results indicated that complex change in knowledge, beliefs, and practice was not a result of particular factors, but rather resulted from a dynamic interaction among factors--the teacher's abilities and desires interacted with elements of the intervention, and contextual influences interacted with the scope of the intervention. Results further indicated that the presence or absence of the critical factors (dissonance, individualization, chemistry, and coalescing) contributed to extensive, moderate, and minimal change in teachers. Findings suggest that training teachers to use a whole language approach would be most effective. (Ten tables and 5 figures are included; 159 references and 10 appendixes documenting instructional processes and teacher ratings are attached.) (PRA)