Helping English learners and students from economically disadvantaged backgrounds read and perform academically as well as their more advantaged peers remains a struggle for many schools seeking equitable outcomes for their students. Research suggests that an increased focus on learning of academic language--the formal language used to read, write, listen, and speak about the topics studied in school--may be one way to boost student and school success. This study investigated WordGen Elementary, a program designed to improve fourth- and fifth-grade students' ability to understand and communicate academic language and their general reading skill. The program included a curriculum of supplemental reading, speaking, and writing activities for students to engage in over a school year, as well as ongoing professional development to support teachers' delivery of the curriculum in their classrooms. About sixty schools from six districts around the country agreed to participate and were assigned at random to implement the program or continue with their typical language instruction programs and practices. The study compared the average reading performance of these two groups of schools to assess the program's effectiveness. Key findings include: (1) The program did not affect the academic language skills or reading performance of students overall; (2) Despite the program's attention to instruction relevant to the specific learning needs of English learners and students from economically disadvantaged backgrounds, the program had no effect on academic language skills or reading performance of either group; and (3) The training and support provided to teachers during the year did not change most aspects of instruction that were targeted by the program, which might explain the lack of effects on student outcomes. [For the Study Highlights, see ED622460. For the appendix, see ED622461.]