This article reports on a four-year longitudinal study which investigates students' use of evaluative language in English as a second language (L2) to talk and write about history in a bilingual education programme. We focus on how four students use linguistic resources to adopt a stance to the content they are learning and develop an authoritative voice, for which they need to use evaluative language, in which people, actions, events and processes are appraised. We combine quantitative analysis of a spoken and written corpus with a qualitative analysis of students' spoken production in one-to-one interviews. Quantitative findings showed similarities and differences in the use of evaluative language among individual students both cross-sectionally and over the four years of study. Moreover, qualitative comparative analysis of the production of two of these students, who were differently rated by their teachers in their English skills, showed clear differences in their abilities to use linguistic resources to construct an appropriate 'historian's' voice in the L2.