This thesis presents an investigation of undergraduate student learning with respect to physics lectures attended in English and Swedish. The work studies three connected areas: student learning patterns, bilingual scientific literacy and disciplinary discourse. Twenty-two physics students at two Swedish universities attended lectures in both English and Swedish as part of their regular undergraduate programme. These lectures were video-taped and used to contextualize in-depth, semi-structured interviews with students. When taught in English the students asked and answered fewer questions and reported be-ing less able to simultaneously follow the lecture and take notes. Students adapted to being taught in English by; asking questions after the lecture, no longer taking notes in class, read-ing sections of work before class or—in the worst case—by using the lecture for mechanical note taking. Analysis of student oral descriptions of the lecture content in both languages identified a small number of students who found it almost impossible to speak about disciplinary concepts in English. These students were first-years who had not been taught in English before. How-ever, the findings suggest that, above a certain threshold level of disciplinary language com-petence, it does not appear to matter which language students are taught in. Finally, the thesis makes a theoretical contribution to educational research. The initial lan-guage perspective is broadened to include a wide range of semiotic resources that are used in the teaching of undergraduate physics. Student learning is then characterized in terms of becoming fluent in a disciplinary discourse. It is posited that in order to achieve an appropri-ate, holistic experience of any given disciplinary concept, students will need to become fluent in a critical constellation of disciplinary semiotic resources.