Although the transparency of a writing system is hypothesized to systematically influence the cognitive skills associated with reading development results of cross language investigations are inconsistent and usually do not address this issue in a developmental context We therefore investigated the cognitive dynamics of reading fluency of different word types in Grades 1-4 in three orthographies differing in degree of transparency (Hungarian Dutch and Portuguese) The overall results showed that the relative strength of the contributions of phonological awareness and rapid naming to word reading fluency shifted as a function of reading expertise The contribution of phonological awareness remained significant in all grades but decreased as a function of grade whereas the contribution of rapid naming increased Orthographic depth systematically modulated the strength of the cognitive contributions to reading but not the overall developmental pattern Together these results indicate that the cognitive development of reading skill is fairly universal (at least for alphabetic scripts) and that differences in orthographic depth will not recruit different cognitive processes but will mainly be expressed in rate of reading development