Semester of Graduation

Summer 2018


Master of Education (MEd)



Document Type



Language is an important area of development addressed in preschool, as it is the foundation for literacy development and the way children express their thoughts and understandings. Mean length utterance (MLU) can be used as a measure of a child’s expressive language development. One intervention that has been used to increase MLU is expansion. Expansion is when an adult responds to a child’s utterance by expanding their sentence to form a more complete or complex sentence. This study used an Expansion Intervention to increase the MLU of preschool aged students. The subjects consisted of three preschool children attending a Title 1, private preschool. The children were identified as behind in language development, according to Teaching Strategies Gold Checkpoint. Using a multiple baseline design, each child’s MLU was calculated across a baseline, intervention and generalization period. The Expansion Intervention was used to increase the child’s MLU while discussing picture books. A generalization probe was conducted six months following the initial expansion intervention to assess the transfer of increased MLU to small group and center environments. The children’s MLU increased by an average 0.62 morphemes when the Expansion Intervention was applied; the generalization probe yielded mixed results. Teachers should consider the use of expansions to increase MLU within the natural routines and activities of the early childhood classroom. Further research is needed to address the transfer of the increase across environments and from a one-to-one situation to a large group situation.



Committee Chair

DiCarlo, Cynthia