The success that one has in learning a second language may be influenced by many variables, including differences in environmental surroundings and individual characteristics of the learner. There have been few studies which systematically examine the influence of these variables on second language learning. This paper examines the effect which certain environmental variables have upon learning to speak English as a second language. Approximately 500 elementary and high school students, enrolled in English as a second language classes in public schools in the Washington, D.C. area, were administered oral production tests at the beginning and end of the school year. These tests, an Oral Interview or the Second Language Oral Production English (SLOPE) Test, were given to students in different schools who were in various types of ESL programs. The preand post-test scores were used to assess the progress made during the school year by these students in learning to speak English. The scores were then examined to describe the influence that multiple variables had upon progress in English oral production. The variables examined included such differences as time in ESL class, size of class, method of teaching and number of foreign students in the school. It was found that all groups of students made significant progress in speaking English during the school year, but that those making most marked improvement were in school settings where the use of English was encouraged and necessary for effective communication.