This study investigated whether L1-Korean L2-English speakers could use (in)definiteness to predict unmentioned (non-)unique referents. In previous studies on the topic, methodological considerations made it difficult to separate the effects of grammar from the effects of non-linguistic knowledge. We used a visual world paradigm eye-tracking task to resolve such issues and designed stimuli that focused only on (in)definiteness. Participants’ eye movements were recorded as they heard “Click on the/a blue circle.” L1 and advanced L2 speakers used definiteness information to predict unique referents before the critical noun (circle) was heard while indefinite articles were not utilized to the same extent. Intermediate L2 speakers relied heavily on color words, not articles, to locate a referent. The results imply that predicting a referent solely based on definiteness (without real-world knowledge) requires substantial advancement in L2 development, and indefinite articles do not predict non-unique referents as clearly as definite articles predict unique referents.
