This study examined how, in some instances, participation in the cultural practices of high school science classrooms created intrapersonal conflict for ethnic minority students. Discourse analysis of videotaped science classroom activities, lectures, and laboratories was the primary methodology employed for analyzing students' discursive identity development. This analysis demonstrated differential appropriation of science discourse as four significant domains of discursive identities emerged: Opposition status, Maintenance status, Incorporation status, and Proficiency status. Students characterized as Opposition Status avoided use of science discourse. Students who exhibited Maintenance Status illustrated a commitment to maintaining their normative discourse behavior, despite a demonstrated ability to appropriate science discourse. Students characterized as Incorporation Status made active attempts to incorporate science discourse into their normative speech patterns, while Proficiency Status students demonstrated a fluency in applying scientific discursive. Implications for science education emerging from the study include the illumination of the need to make the use of specific scientific discourse an explicit component of classroom curriculum.