While the population of bilinguals and English learners continues to rise in our schools, teachers often feel frustrated with their lack of knowledge about best practices to support their multilingual students' language, socioemotional and cognitive development. Teachers' frustration is compounded by the push for assessments in the early years. The aim of this 24-month ethnographic case study is to explore what information linguistically diverse families hold about their bilingual children's language development and use, and how this information can help teachers (1) understand formal and informal assessment data, and (2) create linguistically appropriate support for young bilinguals and their families. The research was drawn from an ethnographic case study of a dual language (Italian-English) preschool in a major metropolitan area. The private dual language preschool provided education for ages 2.8 years to 6 years of age. The families who participated in this study were primarily immigrants, bilingual and middle class. (author abstract)