An intervention, which targeted three- and four-year-old children's oral language, was developed for this study. The intervention was run over twice-weekly sessions, for ten weeks. Incorporating good Early Years practice, the first session in the week was a group shared storybook reading session with a puppet, where dialogic discussion took place and the children practised sequencing the story using visual prompts. The second weekly session consisted of planning, acting out and reviewing a planned pretend play episode based on the storybook which was read in that week's first session. Ninety-four children were randomly assigned to a control or treatment group and were tested at pre- and post-test on a battery of vocabulary and narrative assessments. The results of a Randomised Control Trial were positive in favour of the intervention. The most important of these results was a statistically significant effect on the receptive vocabulary of the children in the treatment group, with a large effect size, as measured by the standardised British Picture Vocabulary Scales (Dunn et al., 1997). There was also a significant effect on productive vocabulary, as measured by a Researcher-Designed Vocabulary Test (RDVT). This test was devised for the purpose of this study, testing one-word vocabulary, taken directly from the storybooks in the intervention. As this is not a norm-referenced, standardised test, caution is advisable in the interpretation of this result. A further positive effect concerned the narrative skills of the children in the treatment group, when compared to the children in a control group - the Mean Length of Utterance (MLU) score was higher in the treatment group, with a medium effect size. By examining the intervention by Randomised Control Trial, this study responds to the call from Lillard et al (2013) for more experimental research on pretend play and narrative. The acknowledgement of the role of the adult in the intervention coupled with the positive effect on the children's MLU and receptive vocabulary mean that the intervention, with further development, has the potential to be used as a Professional Development tool for supporting language development in the Early Years in the UK, in the future.

Speech is the most common and the most fundamental tool used for communication. It has done more for man's progress than any other single factor. Yet this high development of man has been relatively ignored, and for generations speech instruction has been partially neglected in the elementary schools. / "Presented to the Faculty of the School of Education Florida State University." / "In Partial Fulfillment of the Requirements for the Degree of Master of Arts in Education." / "July, 1949." / Advisor: Dr. Robert C. Moon, Major Professor. / Typescript. / Added title page: A two year study of speech instruction of a group of children in Jackson Heights School, Tampa, Florida. / Includes bibliographical references.