This study explores the relationship between English Learners (ELs) in the Texas school system and their outcomes on the State of Texas Assessments of Academic Readiness (STAAR) tests and the Texas English Language Proficiency Assessment System (TELPAS). Schumann's Acculturation Model and Krashen's Input Hypothesis were used as theoretical groundwork to provide a thorough framework for exploring this association. To determine the different levels of acculturation among ELs, this study addressed the research questions posed using quantitative correlational research, specifically, the quantitative data of TELPAS and STAAR from a South Texas school district. The goal of this inquiry recognized patterns and trends within the data to determine if a substantial association exists between TELPAS scores and STAAR outcomes among ELs attending Texas schools. The study regularly found a modestly positive correlation between TELPAS scores and 8th-grade science STAAR scores. The results were statistically significant in all years, demonstrating a favorable association between a higher degree of English language proficiency and enhanced academic performance in the subject of science. Future research should investigate potential relationships and practical applications to develop effective techniques for assisting ELs. These observations can guide educational methods and regulations, ultimately enhancing student achievements and fostering fairness in education. These findings can guide instructional practices, resource allocation, and support systems for ELs. Furthermore, Schumann's Acculturation Model and Krashen's Input Hypothesis adds to the continuing conversation about language acquisition in diverse educational contexts by providing a new angle on the variables influencing ELs' academic success and language proficiency. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]