Recent studies show that English learning students are a growing population within the United States school system. Language barriers have been shown to negatively influence reading scores as well as math scores, and math scores are a predictor of future academic success in many subject areas. This qualitative action research study demonstrates the difficulties many upper-elementary English learning students have understanding number sense (numeracy) in a math classroom setting in Minnesota, United States. The purpose of this study was to explore whether intentional teaching of math vocabulary could alleviate the difficulties upper-elementary English learning students have in understanding, applying, and having confidence in using number sense during math instruction in the general education classroom. In this way, the study aims to assist in overcoming the achievement and opportunity gaps impacting the English learning student population. Interview, observational, and document data were collected from upper-elementary English learning students in my math classroom during the 2022-2023 school year using purposive sampling methods. Qualitative data on vocabulary instructional methods were also collected and used to inform math vocabulary instruction throughout the school year during which the study took place. The results of this study showed that English learning students' understanding, ability, and confidence in math vocabulary improved their math performance in the classroom and decreased their misconceptions surrounding number sense. Although confidence was only improved with single-step word problems, or with a single number sense ability within a multi-step word problem, the overall findings indicate that learning math vocabulary through the use of structured dialogues contributed to greater understanding of number sense components within math word problems and increased students' ability to visualize and explain how to complete the steps needed to do in a math word problem. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]