Research indicates that linguistic input from teachers may affect child vocabulary development in preschool and beyond (Dickinson & Tabors, 2001). Currently, there is little research on the relationship between specific teacher language use in individual interactions on child language outcomes for preschool children at risk for academic delays. The purpose of this study was to determine the effects of teacher vocabulary input and use of strategies for supporting vocabulary learning on children's vocabulary outcomes in three measurement contexts (within session, in language samples, on standardized assessments). Secondary analyses explored the relationship between teacher use of complex syntax and African-American Vernacular English (AAVE) and child use of these language features. Thirty-six teachers provided 60 7-10 minute sessions of Enhanced Milieu Teaching (EMT) to one or two target children with low language in their Head Start classrooms. One EMT session for each teacher-child dyad was transcribed and coded for teacher vocabulary and use of strategies to support vocabulary development, child use of vocabulary, teacher use of EMT strategies, and teacher and child use of complex syntax and AAVE. Descriptive data language indicates great variability for both teacher and child language in EMT sessions. Linear mixed models analysis indicated significant relationships between teacher vocabulary use and supports and proximal (within session) and medial (post-test language sample) measures of child vocabulary use. A negative relationship was found between teacher input and child post-test receptive language scores (distal measure). [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]