This study examines how word characteristics like frequency, concreteness, part of speech and length predict Dutch vocabulary knowledge in 763 adult migrant L2 learners who vary widely in their educational levels in their L1, from minimal to extensive formal education. While the impact of these features on vocabulary learning is well-documented among tertiary-educated adult and adolescent L2 learners in the academic track of secondary education, its effect on low-educated adult L2 learners has hardly been explored. Findings confirm that word frequency, concreteness and length significantly predict receptive vocabulary knowledge, aligning with prior research. However, the study also reveals variations in the predictive power of word frequency and length among adults with different educational backgrounds. These results highlight the necessity to reassess the applicability of findings from current research on L2 receptive vocabulary, particularly concerning adult learners with reduced educational backgrounds.
