ABSTRACT
McArthur-Bates Communicative Development Inventory [CDI] is a precise method to examine language in the early years of life. McArthur-Bates CDI was selected to help to improve Persian Language pathology movement to do researches on early intervention for language disorders in early childhood. The purpose of this study was to define the facial and contextual validity and reliability of the translated infant form of CDI in Persian. This study had an analytical-descriptive and cross-sectional design. The sample included thirty 8-16 months old children, without any mental and genetic problems. They were selected non-randomly from the health centers in Isfahan. Parents of selected children completed two questionnaires including basic information and CDI infant form. The answers were analyzed by calculating internal correlation in questions to define facial and contextual validity and by Cronbach alpha criterion to fix reliability coefficient. Face and content validity were determined through considering a linguist's comments as well as two speech therapists and parents' viewpoints about CDI items. The reliability coefficients for different sections of CDI-infant form were computed respectively from the lowest [?lpha=0.43] to the highest [?lpha=0.98] in regard of general gestures and vocabulary comprehension. The results were expectable considering the goal of determining the validity of translation and sample size. However, it seems that item counts of vocabulary comprehension subscale caused its highest reliability and the least cultural compatibility of general gestures with Iran community caused its lowest reliability