Many adults have trouble with second language acquisition but learn novel native-language words fairly easily. This study explored the role of sublexical native-language patterns on new word acquisition. Twenty English monolinguals learned 48 new written words in five repeated testing blocks. Half were orthographically wordlike (e.g., nish, high neighborhood density and high segment/bigram frequency), while half were not (e.g., gofp, low neighborhood density and low segment/bigram frequency). Participants were faster and more precise at recognizing and generating wordlike items, pointing out a native-language similarity benefit. Individual differences in memory and vocabulary size affected learning, and error analyses pointed out that participants extracted probabilistic information from the new vocabulary. Results propose that language learners benefit from both native-language overlap and regularities within the new language.