Vocabulary size correlates strongly with general language proficiency and is highly predictive of academic skills. Frequency-based vocabulary tests, such as the German VST (‚Vocabulary Size Test‘; Institut für Testforschung und Testentwicklung, 2019; Nation, 2001), are particularly informative. The present study validated this test with 229 fifth and sixth graders from Romansh- and German-instructed primary schools in Graubünden, Switzerland. The study shows a high reliability and internal validity of the German VST as well as a strong correlation of the test with the PPVT-4 (Lenhard et al., 2015) in a sub-sample. The test therefore provides relevant data on the academic vocabulary of students with German as L1, L2 or L3 in the Romansh context
