In recent years there has been a growing interest in the topic of academic language in the context of educational success of (mostly) immigrant children. However, most studies focused on academic language only and did not consider the role of other linguistic resources such as colloquial language for the development of academic language. In this paper, we will discuss the interplay between both registers by presenting an analysis of students’ (n = 3) utterances during a collaborative task in history class. Data was collected in a College for Higher Vocational Education (upper secondary level; ISCS 10) in Vienna where one of the researchers was working as a history teacher. The interaction analysis and interpretation focus on strategies students employ to solve the exercises. The following strategies are identified and explained: mutual explanation for a better understanding of, e. g., technical terms, collective planning and monitoring of the writing process as well as orientation along the structure of other texts. Since colloquial and academic language seem interrelated in these strategies, this paper combines the concept of academic language and linguistic repertoire.