Different writing systems in the world select different units of spoken language for mapping. Do these writing system differences influence how first language (L1) literacy experiences affect cognitive processes in learning to read a second language (L2)? Two groups of college students who were learning to read English as a second language (ESL) were examined for their relative reliance on phonological and orthographic processing in English word identification: Korean students with an alphabetic L1 literacy background, and Chinese students with a (...) nonalphabetic L1 literacy background. In a semantic category judgment task, Korean ESL learners made more false positive errors in judging stimuli that were homophones to category exemplars than they did in judging spelling controls. However, there were no significant differences in responses to stimuli in these two conditions for Chinese ESL learners. Chinese ESL learners, on the other hand, made more accurate responses to stimuli that were less similar in spelling to category exemplars than those that were more similar. Chinese ESL learners may rely less on phonological information and more on orthographic information in identifying English words than their Korean counterparts. Further evidence supporting this argument came from a phoneme deletion task in which Chinese subjects performed more poorly overall than their Korean counterparts and made more errors that were phonologically incorrect but orthographically acceptable. We suggest that cross-writing system differences in L1s and L1 reading skills transfer could be responsible for these ESL performance differences. (shrink)