This technical report presents concrete ways of meeting recommended practice by providing an overview of principles and practices in the area of second language acquisition. It discusses some of the major theories in the area of second language acquisition, as well as the developmental process of first and second language acquisition in the preschool child. This report also considers how the acquisition of a second language can be influenced by multiple variables, especially the presence of a disability. The final section provides strategies for communication support for second language learners with or without disabilities in the preschool classroom when instruction in the native language is not available. It includes extensive references, an annotated bibliography, and a list of available resources from the CLAS Web site. (Author/SG)