Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Health Sciences


Rehabilitation Sciences

First Advisor

Dr. Joneen Lowman

Second Advisor

Dr. Dana Howell


Speech-Language Pathologists (SLPs) provide services to children in schools across the United States primarily in a direct small group service delivery model outside of the regular education classroom. To date little research exists to indicate that direct pull-out service delivery is an effective model in elementary schools for students requiring speech and language therapy. One area that has been studied is the effectiveness of vocabulary intervention among service delivery models. Preliminary findings suggest that students with language and literacy deficits learn vocabulary well within a regular education environment with SLP support. However, there is little consensus on how service delivery models are defined in the literature and what constitutes effective vocabulary instruction in different models. Previous studies comparing service delivery models that target vocabulary were aimed at curricular vocabulary. There are no studies addressing service delivery models targeting instructional verbs and intensity of instruction.

The present study aimed to determine if co-teaching, the process by which two professionals cooperatively plan and teach a lesson, produced differential effects on children’s vocabulary learning as compared to more traditional service delivery practices. To achieve this, a 3 x 3 x 2 randomized experimental design was used to answer the study questions. The independent between group variables were three different service delivery conditions by three student groups. The three service delivery conditions included 1) coteaching between an SLP and a classroom teacher, 2) traditional SLP pullout, and 3) traditional second grade teacher. The three student groups included typical students and two groups of students at risk for literacy deficits, students identified as low socioeconomic status and students with disabilities. The within group dependent variables were the group aggregate scores at pre-test and post-test on two different vocabulary measures used to assess the effects of the three service delivery conditions. Finally, we examined differences in vocabulary instruction among the three service delivery conditions with a focus on dosage, frequency, and intensity of the instruction.

Participants included six classroom teachers within three schools in a moderately sized school district in a suburban Kentucky county, three SLPs and 112 second grade student participants. Nine instructional verbs were taught over the course of six weeks with two 20-minute sessions per week in all service delivery conditions.

Results indicated that all students’ vocabulary knowledge increased significantly regardless of service delivery model. Instruction had significantly greater effects on all students’ expressive word knowledge than receptive word knowledge. However, group differences did emerge. Students identified as typical and low SES groups scored significantly better on the expressive measure than students in the disability group. Students identified in the typical group scored significantly better on the receptive measure than the students in the low SES and disability groups. While no meaningful differences in student learning emerged across delivery models, the teaching episode intensity was higher in conditions involving an SLP as compared to the teacher only condition. Implications for provision of vocabulary instruction using instructional verbs are discussed.

Digital Object Identifier (DOI)