The primary objective of this study was to understand how two dimensions of parent-child book-reading quality – instructional and emotional –interact and relate to learning in a sample of linguistically and culturally diverse, low-income children. Participants included 81 parents and their children who took part in home-based Early Head Start programs in rural counties in the Midwest. Correlation and multiple regression analyses were used to test two hypotheses: (1) the instructional and emotional qualities of parent behavior during shared book reading interact and relate to infants’ and toddlers’ cognitive scores (as measured by the Bayley Scales of Infant Development Second Edition Mental Scale; BSDI-II; Bayley, 1993) and language scores (as measured by the Preschool Language Scale - IV and Preschool Language Scale - IV Spanish; PLS-IV and PLS-IV Spanish; Zimmerman, Steiner, & Pond, 2002; Zimmerman, Steiner, & Pond, 2002) at baseline; and (2) changes in instructional quality and baseline emotional quality of parent behavior during shared book reading interact and relate to changes in children’s cognitive scores over time. Exploratory analyses examined if patterns of relationships varied for families who had different home languages (i.e., English, Spanish). Results demonstrated that instructional and emotional qualities of book reading and home language interacted to predict child cognitive and language scores, both concurrently and over eight months participation in EHS.