This research study examined the process by which non-English speaking students, whose first language is Arabic, learn mathematics in English. Teachers' adaptation was investigated to reflect the effect of change in instructional methods. The effect of communication between teachers, and exchanging ideas about the efficient practice procedure to support English Language Learners, was explored and audiotaped. There is no existing research that analyzes and attempts to understand the process of learning mathematics for Arab-American students. This study is important because it explained how language barriers limit mathematics understanding in ESL students. This research shed light onto the constraining factors that these students face, and will help teachers understand these limitations, allowing them to practice strategies in the classroom to help these students. The researcher's choice of a case study method was determined to be the best way to examine the relationship between mathematics achievement and language proficiency. The research participants were selected from two different schools in a large urban area in a Midwestern state. Two teachers were observed for 28 sessions and interviewed twice, to understand how the teacher creates instructional practices to assist students' acquisition of mathematical knowledge. The researcher interviewed two teachers and five students twice. The researcher used inductive analysis of all participants to distinguish their experiences and knowledge. The researcher employed in-depth analysis of five participants. After collecting data, the researcher used qualitative process analyses which include cutting, coding, categorizing themes and patterns. The researcher organized the data and then used domain analysis, and taxonomic analysis for coding to help the researcher link different pieces together. In this study, the following themes were found: students' impressions, acculturation, classroom discussions, code switching, problem solving, differentiated instruction, methods, learning difficulties/language barrier, and bridging difficulties/ using technology. Three additional themes were discussed; Communication, motivation, and parents' role. In this study, all themes are interrelated and influenced one another. Study limitations and directions for future research were discussed. [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/en-US/products/dissertations/individuals.shtml.]