Research has demonstrated the impact of early oral language development on a child's later reading comprehension. Additionally, research has suggested that teachers' knowledge of effective practices in literacy plays an important role in students' ability to learn to read. The problem is that preschool teachers' knowledge of strategies for developing language is unknown because there is no known instrument for assessing preschool teachers' knowledge of these strategies. The research questions for this study examined the development of an instrument to measure preschool teachers' perceived competency and knowledge of strategies for language development. Chall's reading stage theory was used as the theoretical foundation. This quantitative, nonexperimental study was conducted using a descriptive, cross-sectional design. After a prepilot review of the instrument by literacy experts, a pilot study was completed using a convenience sample of 250 teachers who volunteered to answer the questions on the instrument. Reliability statistics demonstrated a high level of internal consistency for Section 2, promoting extended discourse (a = 0.86) and low levels of internal consistency for the other two sections of the instrument. Further analysis of Section 2 revealed a positive moderate effect size of 0.53, indicating significant variability in test scores between high and low performing teachers. Use of the instrument developed through this study supports social change by providing early childhood professionals information to understand teachers' instructional decisions, determine professional development to increase teachers' knowledge, and inform preschool teachers' preservice preparation. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]