Many adults learn languages with written forms that differ from their first language(s). Empirical research has demonstrated the influential role of written input on developing L2 phonology. However, existing studies are limited by (1) focusing on learning languages that share the same orthographic script, predominantly the Latin alphabet, (2) small sample sizes, and (3) limited consideration of L2 proficiency. This study investigated the influence of Arabic and English written input when lexically encoding the difficult /f-v/ phonological contrast for L1 Arabic-speaking learners of L2 English. A word learning study was completed by 114 L1 Arabic speakers, with varying English proficiency, and 117 L1 English-speaking controls. Mixed-effects modeling of L1 Arabic accuracy revealed an inhibitory effect of any written input when learning words differing by the difficult contrast. Performance improved with increasing L2 proficiency; however, the inhibitory effect of written input for words differing by /f-v/ persisted into high levels of L2 proficiency.
