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GerVLPro: A CEFR-Graded Vocabulary List of L2 Learners' Productive Vocabulary in German

CEFR-graded vocabulary lists are a valuable tool for second-language (L2) learners as they provide guidance on the order in which to acquire vocabulary items. Thus, they are essential for informing computer-assisted language learning solutions that target vocabulary development in learners. However, the vast majority of GVLs are prescriptive in that they determine which items learners should learn at each level, and they provide little information about which items learners actually know. Moreover, in the case of German, almost all established GVLs focus exclusively on learners’ receptive vocabulary. To remedy this, we introduce GerVLPro: A CEFR-Graded Vocabulary List of L2 learners’ Productive vocabulary in German. We derived GerVLPro from a comprehensive aggregation of available CEFR-annotated German L2 learner corpora to represent a wide range of learners and contexts. The resulting list comprises 4,015 lemma-POS entries (A1: 611; A2: 1,134; B1: 903; B2: 1,103; C1: 249; C2: 15), assigned via a normalized share-based method. We then conducted a large-scale cross-evaluation against seven established GVLs and six prominent frequency lists. Despite sizable lexical overlap among resources, we found only weak to moderate alignment with GerVLPro. Finally, we investigated whether Gpt-4o and Gpt-5 can reliably grade the productive vocabulary items in GerVLPro. Although both models exhibit roughly similar predictive capacity, they underperform most of the established GVLs on alignment and do not accurately capture productive difficulty. Overall, our findings suggest that established GVLs, frequency lists, and LLM grading insufficiently reflect the trajectory of learners’ productive vocabulary, underscoring the need for descriptive, learner-based resources such as GerVLPro.