The teaching of reading in different languages should be informed by an effective evidence base. Although most children will eventually become competent, indeed skilled, readers of their languages, the pre-reading (e.g. phonological awareness) and language skills that they bring to school may differ in systematic ways for different language environments. A thorough understanding of potential differences is required if literacy teaching is to be optimized in different languages. Here we propose a theoretical framework based on a psycholinguistic grain size approach to guide the collection of evidence in different countries. We argue that the development of reading depends on children's phonological awareness in all languages studied to date. However, we propose that because languages vary in the consistency with which phonology is represented in orthography, there are developmental differences in the grain size of lexical representations, and accompanying differences in developmental reading strategies across orthographies.