There are currently five million English language learners (ELLs) enrolled in America's K–12 public schools. According to the Arizona Department of Education, over 138,000 Arizona students were labeled ELL for the 2008–2009 school year. In 2005, 71% of 8^th grade ELLs and 73% of 4 ^th grade ELLs scored below the “basic” level in reading on the National Assessment of Educational Progress (NAEP). In an effort to address this achievement shortfall, the Arizona state legislature mandated a policy segregating children who are learning English, primarily of Latin-American origin, from the mainstream student population into English Language Development (ELD) classes for four hours each day.

Achievement is correlated with perceptions regarding one's own capabilities. Albert Bandura's Social Cognitive Theory provides the theoretical framework for this study. Social cognitive theory identifies four sources of self-efficacy beliefs: mastery experiences, vicarious experiences, social persuasions, and physiological states. This mixed methods study utilizes a questionnaire, individual interviews and focus groups to investigate the following question: (1) What are the most influential sources of self-efficacy for Arizona's ELLs in the domain of verbal English acquisition?

An Analysis of Variance (ANOVA) of the data collected from the 226 questionnaire respondents indicates that there is no statistical difference in the influences exerted by each of the self-efficacy sources. This is not consistent with previous research pointing to mastery experience as the most influential efficacy source. For the subgroup of ELLs with two years or less experience learning to speak English, vicarious experience, specifically peer modeling, was statistically more influential, hinting at fundamental flaws in the segregated environments mandated in Arizona which systematically separate essential peer language models from ELL students, placing them in different educational tracks. Findings from this study point to the interconnectedness between all four sources of self-efficacy, a point to be considered when designing programs to support positive self-efficacy development for ELLs. Recommendations for increasing the self-efficacy of ELLs are presented.