Can adult L2 learners develop nativelike competence for structures that are not instantiated in their first language? This experimental study examines the effect of distance between noun and adjective on English L1-Spanish L2 learners' ability to detect adjective discord, using an acceptability judgment task. Results show that 1) beginners, but not intermediates, are affected by increases in linear and syntactic distance, and 2) task effects are found between a more explicit and less explicit offline task. Explanations of the results by a UG-constrained developmental stage and by Processability Theory are evaluated; Processability Theory better fits the data. Processing difficulties, not representational deficits, are responsible for poor agreement performance in beginners.