This paper provides a detailed analysis of the mathematical communication involving a pair of high school calculus students who are English language learners. The paper focuses on the word-use, gestures and dragging actions in the student-pair communication about calculus concepts when paper-based static and then touchscreen dynamic diagrams. Findings suggest that the students relied on gestures and dragging as multimodal resources to communicate about dynamic aspects of calculus. Moreover, examining the interplay between language, gestures, dragging and diagrams made it possible to uncover English language learners' competencies in mathematical communications. This paper points to an expanded view of bilingual learners' communication that includes gestures, dragging and diagrams. [For the complete proceedings, see ED597799.]