Bilingualism continues to increase with more than 350 different languages spoken in the United States, and more than 21% of people over the age of five (approximately 66 million people) speaking a language other than English at home (U.S. Census Bureau, 2020). Many bilingual children in the US speak a minority first language (L1) and English as their second language (L2). For a bilingual child, development of both languages are important for different purposes and contexts. Although the L1 is oftentimes not the language of school instruction in the US, L1 maintenance can lead to closer family cohesion (Park et al., 2012), a stronger sense of identity (Phinney et al., 2001) and overall better health outcomes (Mulvaney-Day et al., 2007). However, bilingual children are at risk for L1 attrition (Pearson, 2007) and this risk is even greater for bilingual children with a language disorder (Ebert et al., 2014). Speech-language pathologists (SLPs) lack resources to assess and treat bilingual children, especially in the L1. Despite the evidence for best practice, SLPs have resorted to an English-only approach to assessment and intervention (e.g., Caesar & Kohler, 2007, Williams & Mcleod, 2012, Arias & Friberg, 2017). Clearly, more work is needed to improve the quality of care for bilingual children. There are limited resources on how to include L1 in assessment and intervention as compared to the L2 (English). This dissertation contributes to evidence-based resources for SLPs to better incorporate the L1 and, in turn, improve service delivery for bilingual children and families.