The current longitudinal, mixed-methods dissertation explored how various Family Language Policy (FLP) factors (including parent and child language ideologies, practices, and management) influence "Español"-English (hereafter, "Españ"Eng) bilingual students' home language maintenance/loss and their bilingual development. "Españ"Eng bilingual students, who have been commonly referred to as English Learners or Emergent Bilinguals, are students whose first or home language is Spanish and who are simultaneously or sequentially acquiring English. Despite their bilingualism, "Españ"Eng bilingual students attend schools in the United States that uphold "monoglossic" language ideologies, which promote English monolingualism and the separation of languages, failing to acknowledge and value their bilingual linguistic repertoire. Such "monoglossic" language ideologies, which promote English acquisition at the expense of students' home language development, puts "Españ"Eng bilingual students at risk of both losing their home language and being labeled as academically and linguistically deficient. The purpose of this study was to provide an anti-deficit perspective of "Españ"Eng bilingual students and their families by acknowledging and honoring their full linguistic repertoire, not solely their English proficiency. Interviews with eight parents and 18 "Españ"Eng bilingual students (nine of whom are in EO classrooms and nine of whom are in DL classrooms), along with dyadic family interviews and longitudinal English and Spanish tests of achievement results for these students, informed the results of this study. In regard to FLP, students in both EO and DL classrooms were exposed to a language separation ideology both at home and at school. Most students took roles as language teachers and translators, which was an exception to the language separation ideology, while other students rejected their parents Spanish-only rule at home. While parents and children in DL classrooms identified fear of home language loss and the necessity to speak Spanish at home as motivation for their language management, parents and children in EO classrooms cited their desire to compensate for the child's lack of exposure to Spanish instruction at school, as well as traveling and future job benefits, all as motivation for their language management. For the most part, with only a few exceptions, students in both DL and EO classrooms experienced growth in their Spanish and English levels of proficiency and development. This growth may have been a sign of home language maintenance. Despite their growth, students in DL classrooms outperformed students in EO classrooms in both Spanish and English proficiency and development. Even if the tests of achievement deemed students in EO classrooms' Spanish reading, math, and writing proficiencies to be "limited," students' self-reported proficiencies highlighted how these students' Spanish speaking/verbal abilities were high in that they successfully translated for their loved ones, "teach [taught]" others how to speak either Spanish or English, and communicated with linguistically diverse individuals. The findings from this study have implications for ways in which parents, students, teachers, administrators, policy makers, and other key stakeholders can foster home language maintenance and more accurately measure and honor "Españ"Eng bilingual students' bilingual development, regardless of whether they are in DL or EO classrooms. All parents in this study aspired to raise bilingual and biliterate children but used different means (i.e., language of instruction) to meet such aspiration. [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.]