What language demands count in subject-matter classrooms?

To overcome language challenges in subject-matter school achievement, mainstream teachers of all subjects are requested to foster students’ academic language proficiency in subject-matter classrooms without being systematically prepared for this job, for instance, for the question what kind of language demands count as relevant in their classroom. The study investigates how 223 secondary mathematics teachers analyze students’ written explanations in a diagnostic activity aimed at unpacking the language demands they identify as relevant. The study reveals that teachers activate a large variety of different diagnostic categories, and many teachers focus on language demands that are too peripheral to subject-matter learning. These teachers’ unproductive focus seems to be connected to their language-related orientations, which were captured in a questionnaire. The statistical analysis of the data shows some language-related orientations are significantly connected to the activation of more suitable categories. Thus, which language demands teachers notice and value in students’ mathematical explanations seems to influence whether they assume responsibility for language learning. Consequences for professional development are discussed.