This longitudinal study will design and implement an intervention program to improve the language skills of Spanish-English bilingual kindergarten students and to assess the impact of the intervention on their early literacy skills. The intervention program will focus on improving vocabulary and extended discourse skills, aspects of children's oral language skills that have been shown to be related to literacy outcomes and that research has identified as areas of weakness for young bilingual students. Using a quasi-experimental design, the researcher will develop and test three different types of interventions to explore whether improved Spanish vocabulary skills transfer to improved English performance automatically, or whether their effect depends on linking enrichment in Spanish specifically to new English learning. Kindergarten children from Spanish-speaking backgrounds will be assigned to one of four groups[unreadable][unreadable]Spanish home intervention, English classroom intervention, Spanish home intervention linked to English classroom intervention, or a no-intervention control group. The study design has five aims: 1. To develop and implement an intervention program designed to improve Spanish-speaking children's oral language skills; 2. To compare the impact of delivering the program in the native language at home with the impact of delivering it in English in the kindergarten classroom and the impact ofdelivering it in both languages and venues simultaneously; 3. To explore the nature of transfer from Spanish to English by explicitly comparing outcomes for the Spanish-only to the Spanish-plus-English versions of the program; 4. To compare the impact of the program on children with varying degrees of skill in Spanish and English;and 5. To examine the relationships between the short-term effects of the intervention on oral English skills and its long-term effects on English literacy through second grade. Unifying the this subproject with the other three subprojects and two cores proposed in this program project is a shared model for the development of word knowledge and comprehension skills, the approaches used to promote word knowledge, and the methods used in the conduct of the research. Like the other subprojects, it begins with the model of L2 reading comprehension outlined by Proctor, Carlo, August, &Snow (2005), which states that decoding and oral language skills are important factors in the reading process, with oral language (and vocabulary knowledge, in particular) being stronger reading predictors of comprehension. It also builds on findings from the cross-project analyses cited in the Research Program Overview that indicate the instrumental role that vocabulary plays in reading comprehension. Like the other subprojects, this study recognizes that vocabulary is one of best predictors of reading comprehension, that it is a complex construct that has many components, that it is learned in multiple contexts at both home and school, that it is a domain of particular weakness for ELLs, and that it is a domain in which the workings of first to second language transfer have been only minimally investigated. Like the interventions outlined in Subprojects 3 and 4, the design of the interventions proposed here have been framed using the four-pronged vocabulary program proposed by Graves (2006). That program outlines four components of an effective vocabulary program: providing rich and varied language experiences;teaching individual words;teaching word-learning strategies;and fostering word consciousness. There is strong evidence that these four components are effective strategies for improving vocabulary knowledge. Because this study is concerned with young children the focus of the intervention is on providing rich and varied language experiences and teaching individual words. This study also shares a commitment to sound methodology with the other proposed studies in the program project. We will collect longitudinal data and use individual and multilevel growth modeling in order to shed light on the complex relationships among oral language and literacy skills, both within language and across languages. Growth modeling will also allow for an examination of those skills that have an effect on developmental trajectories in English and/or Spanish. We will use mentoring and professional development to ensure that the interventions are well implemented;measure home and classroom contextual variables that might influence students'outcomes;and employ measures that are psychometrically sound as well as consistent with those used by the other subprojects to make cross-project analyses possible.