The ethnolinguistic terms in which the children of Dominican immigrants in Rhode Island think of themselves, i.e. as “Spanish” or “Hispanic,” are frequently at odds with the phenotype-based racial terms “Black” or “African American,” applied to them by others in the United States. Spanish language is central to resisting such phenotype-racial categorization, which denies Dominican Americans their Hispanic ethnicity. Through discourse analysis of naturally occurring peer interaction at a high school, this article shows how a Dominican American who is phenotypically indistinguishable from African Americans uses language, in both intra- and inter-ethnic contexts, to negotiate identity and resist ascription to totalizing phenotype-racial categories. In using language to resist such hegemonic social categorization, the Dominican second generation is contributing to the transformation of existing social categories and the constitution of new ones in the US.