Bilingual children, the majority of whom are Spanish-English learners, now constitute over a third of the preschool population in the United States (Migration Policy Institute, 2021). Bilingual children and their families face multiple barriers to high-quality early childhood education, which are largely due to the underutilization of culturally and linguistically responsive academic assessment, instruction, and family engagement practices (Adair, 2015; Cuba, 2020; McWayne et al., 2022; Nores et al., 2018; Paulick et al., 2023). However, preschool practices for promoting bilingualism can be challenging to implement because bilingual children are highly heterogeneous, and there is relatively little research available on typical development and home environments in this population (National Academies of Sciences, 2017; What Works Clearinghouse, 2023).This dissertation consists of two person-centered studies aimed at advancing the field's understanding of heterogeneity in the preschool development and home environments of Spanish-English bilingual children. The first study identified profiles of Spanish and English preacademic skills using fall and spring oral language, pre-literacy, and early numeracy assessment data from 348 pre-kindergarten children. Demographic predictors of children's profiles and changes from fall to spring in the number and type of profiles, as well as profile membership were examined. Four profiles of bilingual development were selected. Profiles were distinguished by patterns of English-Dominant Average, Spanish-Dominant Low, Balanced Hig; and Balanced Average pre-academic skills. The number and types of profiles remained stable from fall to spring, as did children's individual profile membership. Child age and maternal education were key factors that differentiated children in the English-Dominant Average and Balanced High profiles from children in the other profiles. The second study identified profiles of bilingual home environments using family questionnaire data from 348 Spanish-English bilingual pre-kindergarteners. Specifically, home environment profiles were generated based on patterns of variability in the amount of language exposure, child language use, and parent-child activities that occurred in mostly or all Spanish, mostly or all English, and equal proportions of both languages. Additionally, demographic predictors of home environment profiles were examined, followed by an investigation of the relationship between home environment profiles and child outcome profiles. Three home profiles were selected, including an English-Dominant Home Environment, a Dual-Language Home Environment, and a Spanish-Dominant Home Environment. Child age and maternal levels of education significantly influenced children's membership in the Dual-Language Home Environment and the English-Dominant Home Environment. Additionally, children were more likely to be classified in the child outcome profile with patterns of language dominance or balanced bilingualism corresponding to their home environment profile. The profiles identified in these studies help distill the complexity of bilingual development and bilingual home environments without obscuring meaningful variability. Findings have important implications for developing culturally and linguistically responsive assessment, instruction, and family engagement practices that center and celebrate bilingualism as an academic asset. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]