The present paper investigates content-teacher fluency in bilingual classrooms. Adopting a CLIL teaching literacy perspective (Sandberg, 2019), building on the Noticing Hypothesis (Schmidt, 1990) and the concept of grammatical metaphor (Magnusson, 2011), the aim of the study is to describe, explain and reflect on content-teachers’ conceptualisation of school-related, academic language (Lindberg, 2009) in bilingual classrooms. In the investigation, content teachers working in bilingual high school study programmes were observed and interviewed. In the emerging data, the professionals demonstrated notions of content teaching through two languages at times as gap-filling activities. As experts in their field, they expressed no anxiety as to the content areas to be taught. Rather, the linguistic wrapping was found to be an obstacle. From time to time, the teachers had to search for words to describe and explain pronomena. They found elaborations on topics difficult because they did not to a great extent know what school-related, academic language to use. Moreover, the teachers could not teach their students to use this language because they were not aware when and how to approach this language. It became clear that they did not have enough knowledge, or terminology, to address the linguistic side of the phenomena they were focusing on in their teaching. With the Nocting Hypohtesis in mind, the content teachers could be alerted to the linguistic spaces that mediate the learning and teaching of content areas in the school subjects. Learning to identify words and phrases as grammatical metaphors that be unpacked before continuing, the fluency of teacher language could be enhanced, and thus the learning potential for the students could increase. For teachers and learners in classrooms where several languages are at work, language awareness is likely to evolve implicitly. For significant improvement in CLIL teacher fluency, however, and for potential success in student learning, explicit attention to linguistic features is necessary, As shown in the study, the Noticing Hypotheis is to be noticed in the development of CLIL teaching literacy, and grammatical metaphor could be a helpful mediator in this process.