Research Findings: The objective of this study was to understand how instructional book-reading style and emotional quality of reading interact and relate to cognitive skills in a sample of at-risk infants and toddlers. Participants were 81 parents and their children participating in Early Head Start programs in the rural Midwest. Correlation and multiple regression analyses were used to test the hypothesis that parental book-reading instructional style and emotional quality interact and relate to changes in children's cognitive scores for culturally and linguistically diverse families. Results included that there were variations in how book-reading qualities interacted and related to changes in child cognitive scores for families whose primary home languages were either English or Spanish. Practice or Policy: The results of this study are discussed in conjunction with findings from a previous study published in this journal that examined concurrent relationships in the same sample of Early Head Start families. Combined, findings of these studies underscore a need to further explore potentially complex patterns of relationships among parental literacy behaviors and child knowledge, concurrently and across time, for culturally and linguistically diverse families. Better understanding these patterns could inform the development and implementation of culturally sensitive intervention approaches designed to support high-quality parent-child book reading.