This mixed-methods study examines the influence of linguistic aspects on fifth-grade Emirati students' bilingualism in English and Arabic. In the first phase, 350 fifth-grade students and their teachers completed surveys on students' phonology, syntax, and semantics abilities in both languages. Interviews were also conducted with select students and teachers. The findings showed students had lower proficiency in English linguistic elements compared to Arabic. Students' biliteracy practices were insufficient due to linguistic difficulties. English teachers believed students needed more scaffolding strategies due to discrepancies in the instructional environment compared to Arabic teachers who viewed students' linguistic abilities more positively. The study recommends a reconceptualization of bilingualism and biliteracy practices with