Predictions derived from the central processing and script dependent hypotheses were assessed by measuring the reading ability of 116 Grade 2–5 Herero–English bilingual children in Namibia ranging in age from 7 to 12 and investigating possible predictors of word reading among measures of cognitive/linguistic processes. Tasks included measures of word reading, decoding, phonological awareness, verbal and spatial memory, rapid naming, semantic fluency, sound discrimination, listening comprehension and non-verbal reasoning. Faster rates of improvement in literacy within the more transparent language (Herero) supported the predictions of the script dependent hypothesis. However, the central processing hypothesis was also supported by evidence indicating that common underlying cognitive-linguistic processing skills predicted literacy levels across the two languages. The results argue for the importance of phonological processing skills for the development of literacy skills across languages/scripts and show that phonological skills in the L2 can be reliable predictors of literacy in the L1.