PurposeTo communicate with linguistically diverse patients, medical students and physicians often use their non-English-language skills. However, there is no standard protocol to determine whether those skills are adequate before patient care. This causes many physicians, institutions, educators, and learners to forgo non-English-language proficiency assessment altogether. The purpose of this study is to report on the development, refinement, and interrater reliability of the Physician Oral Language Observation Matrix (POLOM), a rater-based tool assessing 6 language skill categories observed during clinical interactions: comprehension, fluency/ fluidity, vocabulary, pronunciation, grammar, and communication. This study focused on the use of the POLOM in Spanish interactions.