A study examined variability in learner progress through a pre-university intensive English-as-a-Second-Language program as it relates to 36 language learning background variables (e.g., formal English training and exposure, motivation, etc.) and four entry-level proficiency variables. Subjects were 201 Indiana University students. Success was measured by passage from one proficiency level to another/others over the period of program enrollment, and three groups were identified: high, medium, and low success learners. Analysis of the data resulted in identification of nine language learning background variables most closely associated with success patterns. These include: school levels at which English was learned; number of family members who have studied in English-speaking countries; previous exposure to English as the language of instruction; number of years since English was last studied; number of years of university English; teaching focus in English class; first language; attitudes toward English class; and stated purpose for learning English. Results are summarized. The research method applied in this study was found useful for identifying significant variables associated with language learning. Contains 12 references. (MSE)