Validity and reliability study of LITMUS Turkish sentence repetition test

This study aimed to analyze the validity and reliability of the LITMUS Turkish Sentence Repetition Test (LITMUS TR) and to introduce the test into Turkish. The study was conducted with 250 children with typical language development and 44 children with developmental language disorders (DLD). In addition to LITMUS TR, Turkish School Age Language Development Test (TODİL) was applied. For the scope validity, it was explained which standards were adopted during the creation of LITMUS TR and which experts' opinions were used. With the construct validity analysis, it was shown that the test could distinguish the groups, there was a significant relationship with the age variable, and the gender variable was not a determinant in test performance. Item difficulty and item discrimination values were reported. Each item in the test was found compatible with the whole test. For criterion validity it was presented that there was a significant relationship between LITMUS TR and all subtests of TODIL. The reliability coefficient of the test was found to be very high both for the general sample and for the selected subgroups. The stability analysis was performed using the test-retest method. Inter-rater reliability information was provided for equivalence analysis. The diagnostic accuracy of LITMUS TR was determined by ROC curve analysis, and it was found that the test could accurately distinguish the groups at 80% and above. As a result, this study shows that LITMUS TR is a valid and reliable tool to be used in diagnosing DLD as a supportive objective measure. Key Words: Developmental Language Disorder, Sentence Repetition Test, Validity, Reliability, Diagnostic Accuracy, Early Intervention.