This study investigated how newcomer emergent bilinguals made meaning in two 9th-grade biology classrooms. Methods relevant to naturalistic inquiry were used to collect and analyze data. Findings indicate that newcomers bridged aspects of personal experiences with social competencies valued in classrooms through using heritage languages, engaging as brokers and collaborators, and attempting to realize goals of learning English and content simultaneously. Findings also show that misalignments between social competence and personal experience constrained meaning-making. This study illustrates a need for activities that reflect and expand newcomer resources and experiences, and for activities that can take shape through student participation.