The effects of orthographic complexity and diglossia on letter naming in Arabic: A developmental study

The purpose of the study was to examine the influence of orthographic complexity and diglossia on letter naming and automaticity in Arabic. Two experiments were carried out by 31 first graders, 30 third graders, 34 fifth graders and 20 university students. In the first experiment we took advantage of the Arabic orthographic variation in letter shape, and compared the Stroop effect for correctly written and orthographically distorted words. All participants revealed a Stroop effect with both types of words, but only first graders showed the same degree of interference with distorted and correctly written words. We interpret these results to reflect the development of automaticity in reading. In the second experiment, six letter-naming tests were performed. The results showed that retrieval time of naming letters or the sounds that these letters represent decreased inversely with age. A different pattern was found between the school-age children and the university students. In children, the relationships between types of tests of retrieval speed remained constant: retrieval of letter names or sounds which do not have visual or phonological neighbours was the fastest, and of letter names representing sounds that do not exist in spoken Arabic was the slowest. There was no effect of changing letter shape. However, among the university students only changing letter shape affected the speed of responses. We interpret these results to reflect different representations of letter categories in adults and children. The findings have implications for models of reading development in Arabic.