Academic language has been the subject of much interdisciplinary discourse. However, a major problem arises when attempting to operationalize the construct of academic language. A common approach is to determine typical grammatical and lexical features. However, such compilations are not suitable for describing and explaining linguistic functions and actions in academic language. They are thus also not suitable for investigating academic language skills, since they neglect a central aspect of language. This problem is addressed in the present article, which considers academic language skills from a pragmatic and functional perspective. First, transdisciplinary aspects concerning structure, diagnosis, acquisition, teaching and standards of academic language skills are considered. On the basis of these findings, a heuristic model for representing different aspects of academic language skills is presented. The three fields of the model consider relevant cultural conditions (domains, functions, fields of knowledge, tasks, interactions and media), academic language actions (modes, units) and relevant individual resources (cognitive, motivational, volitional). These are then discussed with reference to three central concepts in the German-language discourse on academic language: „Alltägliche Wissenschaftssprache“, „Diskurspraktiken“ and „Textprozeduren“.