The purpose of this single-subject longitudinal study was to examine the Spanish and English biliterate development of U.S. Latino Spanish/English speaking students, who we call emerging bilingual students, as they participated in an innovative biliteracy instructional program titled Literacy Squared®. Findings indicate that across the three years of the study, participating students made gains in Spanish and English reading and writing. This study provides support for Literacy Squared as an innovative biliterate program. Further, the study provides evidence for the need to consider alternative methods to document Latino Spanish/English students' biliteracy development such as through the use of biliterate trajectories.