In the current study of applied cognitive linguistics (CL), schematic diagrams that represent generalizations of physical-spatial experience were applied in a computer-based tutor that trained English prepositions for second language (L2) learners. Behavioral and electrophysiological (ERP) measures were used to examine whether schematic-diagram feedback provided by the tutor had an instructional advantage over the minimally informed correctness feedback. Behavioral results confirmed this prediction and further revealed that the treatment difference was more striking when the participants had a lower L2 proficiency. The ERP results also supported the prediction. Violation uses of prepositions yielded an N270 and an N400. Schematic-diagram feedback motivated significant changes in brain potentials, whereas correctness feedback failed to do so. Overall, our findings suggest that CL-inspired instruction of a relatively short duration led to significant improvements in learners' behavioral productive performance and in their sensitivity to semantic violation of preposition use during online sentence processing. The study provided strong neurolinguistic evidence for CL-inspired pedagogy in supporting L2 learning.