Purpose: This study examines the response patterns of 278 Spanish-English dual language learners (DLLs) on a standardized test of receptive English vocabulary. Method: Investigators analyzed responses to 131 items on the Peabody Picture Vocabulary Test--Fourth Edition (Dunn & Dunn, 2007) focusing on differential accuracy on items influenced by (a) cross-linguistic overlap in phonology, (b) part of speech, and (c) word frequency. Results: The differential response patterns showed cross-linguistic overlap, part of speech, and word frequency were significant predictors of the likelihood of obtaining a correct response above and beyond the expected difficulty level of the item. Conclusions: All 3 factors predicted DLLs' response patterns beyond expected difficulty. Items with the highest likelihood of error included words with few or no shared features between Spanish and English translation equivalents, verbs or modifiers, and words with low frequency of occurrence. Implications: Researchers should consider a cross-linguistic overlap in addition to part of speech and word frequency when designing vocabulary assessments for DLLs or utilizing such tests in research and clinical practice. Recognizing potential bias, clinicians should triangulate the appraisal of DLLs' language skills across multiple sources or measures and use caution when interpreting vocabulary assessments.