When studying multilingual children and adolescents, it is crucial to ask about the age of onset and/or length of exposure to the languages in question before classifying them as L2 learners or not. In our semi-systematic review of 138 papers from the field of research on German as a Second Language (GSL), we ask to what extent this distinction is drawn in the field. GSL is concerned with at least two fundamentally different groups. One group is multilingual children and adolescents who acquire German as one of their first languages or as their early L2. The other group is the first generation of newly immigrated children, who clearly acquire German as their second language. We reviewed a data sample of n=138 papers that were coded according to explicit and implicit features related to GSL speakers. With the help of relative frequencies and association analyses we show that GSL speakers are mainly conceptualized as ``bi- or multilingual'' and speakers with ``languages other than German'' in their repertoire with ``insufficient German competence'' experiencing ``educational disadvantages'' in schools. Common psycholinguistic L2-criteria such as Age of Onset (AoO) occur surprisingly rarely in our data. These findings suggest a deficit-oriented conceptualization of GSL speakers and reinforce tendencies of Othering. In light of these findings, we argue for a narrowing of the concept of GSL and a better disclosure of L2-learner-specific metadata.