Clinical Question: Would a dual language learning (DLL) child age 2+ years with delayed or impaired vocabulary development (P) show gains in both languages when supplementing intervention in his or her second language (L2) with an indirect speech-language pathologist-supervised or prompted first language (L1) intervention (I) in comparison to no supplemental intervention in the child's home language or no intervention(C) as shown by L1 or L2 vocabulary growth (O)? Method: Systematic Review. Study Sources: PubMed, ERIC, speechBITE. Search Terms: bilingual intervention language OR bilingual intervention vocabulary OR home-language intervention AND bilingual* OR dual language learn* OR DLL OR preschool child* OR Spanish speak* OR home language OR English language learn*. Number of Included Studies: 3. Primary Results: 1. Young DLLs with low vocabulary skills who are provided with bilingual intervention are capable of expanding their vocabularies in both of their languages. 2. Emerging evidence indicates that monolingual SLPs can promote vocabulary acquisition in young DLLs' home language and majority language. 3. Parent involvement with systematic language stimulation, parent mediated dialogic book reading, and the use of computer-based bilingual presentations appear to be promising ways to implement home language vocabulary goals for monolingual SLPs. All approaches warrant further evaluation with bigger sample sizes, rigorous controlled designs, and diverse populations. Conclusions: Although there is a growing need for bilingual intervention for DLL preschoolers with delayed or impaired vocabulary acquisition, few studies have examined approaches that can be readily implemented by monolingual SLPs. While emerging trends suggest that strategies implemented by monolingual SLPs can facilitate L2 vocabulary growth with the added benefit of supporting L1 vocabulary learning, monolingual SLPs need more evidence-based recommendations to improve the vocabulary outcomes of the diverse range of DLLs they serve in everyday practice.