“…This not only poses an issue of time, but also requires strong diagnostic skills (Black & Wiliam, 2009; for an overview, see Kärner, Warwas, & Schumann, 2021). International findings show that teachers often lack knowledge of basic language constructs for this purpose (for Canada, England, New Zealand and the USA, see Washburn, Binks-Cantrell, Joshi, Martin-Chang, & Arrow, 2016; for Finland, see Aro & Björn, 2016; for Germany, see Corvacho del Toro, 2013) and that the accuracy of their diagnostic judgments is limited (for an overview, see Kärner et al, 2021). As a successful start in literacy acquisition has a positive long-term effect on later performance, and early deficits are difficult to make up for later (see longitudinal study by Sparks, Patton, & Murdoch, 2014), it is important to develop procedures that enable a differentiated diagnosis of students' spelling abilities so that appropriate exercises can be provided on this basis (Lee, Chung, Zhang, Abedi, & Warschauer, 2020).…”