At present, no research has investigated the effect of tester accent on the performance of children with language delay. This is a major gap in the knowledge of speech and language therapists and has implications for several other professions such as psychologists and teachers. As is the case with younger typically developing children, there are reasons to expect that children with language delay, may perform less well on tests, when sentences are spoken in an unfamiliar accent compared to a familiar one. Although a tester with an unfamiliar accent may have speech that is clear, its unfamiliarity may place an additional burden on the child’s already reduced language processing capabilities. If the tester’s accent diminishes children’s performance in a test setting (as previous research has shown can occur in adult populations), then this could lead to a situation where language problems are over-diagnosed and as a result children may be referred unnecessarily for speech and language therapy. This research project aims to investigate if accent has an effect on children’s performance and consequently to ensure that children receive an accurate assessment of their language ability.