The teaching and research communities in mathematics education agree that mathematical discussions pose challenges in elementary classrooms. These challenges continue to motivate research on mathematical discussions, with a focus on how students use talk in discussions. This study addresses the question, "What can teachers and researchers learn about mathematical discussions, when such discussions are led by bilingual students?" Evidence of bilingual mathematical discussions at the student-to-student level is analyzed, and implications for both Spanish-English bilingual and English monolingual mathematics instruction are offered.