This report compiles findings related to how long it takes English language learners to become proficient in speaking English and how long it takes them to master enough English to be successful in classrooms where all academic content is in English. The report draws on findings from four schools. Two schools are in the San Francisco Bay area and two schools are in Canada. The authors collect their own data from the California schools and rely on previous research for the Canadian schools.
Hakuta, K., Butler, Y.G., and Witt, D. (2000, January). How long does it take English language learners to develop oral proficiency and academic proficiency in English? Stanford, CA: University of California Linguistic Minority Research Institute.