This quantitative study derived from an on-going federal experimental research project targeting Spanish-speaking English language learners (ELLs) receiving services in four program models: control/experimental transitional bilingual education (TBE) and control/experimental structured English immersion (SEI). The purpose of my study was (a) to capture the growth trajectory and rate of oral English acquisition, (b) to investigate the role of oral English development in acquiring English reading skills, and (c) to compare program models in order to identify practices that promote ELLs’ English oral and reading competency at the early elementary level. Structural equation modeling was utilized. Participants consisted of 534 Spanish-speaking ELLs who started at kindergarten and continued through first grade in their respective models. Striking similarities were found among the four instructional models that English oral proficiency improved significantly (p < .05) in a linear fashion over two years. However, the magnitude differed in that the experimental TBE demonstrated a steeper growth (p < .025) than that of the control group that started at the same level. Even though experimental SEI group started at a much lower level in oral English, they progressed at a rate significantly higher (p < .05) than that of the control group. In relation to English reading comprehension, for experimental SEI groups, the initial level of English oral proficiency is of great concern in reading achievement (p < .05). For both TBE groups, effective intervention is desired because the growth of English oral proficiency strongly impacts reading achievement (p < .05), and, in addition, initial level strongly predicts reading comprehension. The intervention was successfully implemented so that students advanced to a substantial amount in academic English oray. It is also evident that first language (L1) instruction did not impede the learning of a second language. On the contrary, for those students receiving a larger proportion of L1 instruction, alterations in program models are needed to nurture English oracy at a faster rate of growth, which in turn facilitates English literacy acquisition. Findings also indicate that without effective English intervention, students placed in control TBE classrooms remain below all the students in oral English proficiency.