Objective: The goal of this research is to attest Covert Repair Hypothesis (CRH) i.e, discovering the phonological loop of the word production process in stuttering children.

Materials & Methods: In this analytical (Case – Control) research, forty bisyllabic and trisyllabic nonwords were designed. After the pilot study, these nonwords were presented to twelve stuttering children with the ages 5-8 and twelve nonstuttering children by the use of DMDX software. Children were asked to repeat the nonwords immediately after hearing them, the reaction time were recorded by the DMDX. The number of phonological errors and correct responses were determined.

Results: Findings proved that stuttering children in all its forms except of reaction time of trisyllabic nonwords had a weak performance. However, the research results were not statistically significant.

Conclusion: The study evidences show differences between stuttering and nonstuttering children performances. This may outline the possible of defect in language processes of stuttering children, especially in phonological encoding of word production mechanism. Also, the difference pattern between groups had coordination with CRH assumptions.