Prosody signals important aspects of meaning, and hence, is crucial for language comprehension and learning, yet remains under-investigated in second-language (L2) processing. The present electrophysiology study investigates the use of prosody to cue information structure, in particular, the use of contrastive pitch accent (L+H*) to define the set of elements that are contrasted. For instance, in "We ate Angela's cake, but saved BENjamin's cake," the pitch accent on "Benjamin's" is a cue that two cakes are contrasted; "BENjamin's ice cream" is not plausible in this context. Native English speakers showed a large negativity on the target noun ("cake") when the preceding possessive was inappropriately accented. Event-related brain potential (ERP) results from Mandarin-Chinese L2 learners of English suggest they did not use contrastive pitch accent to cue the contrast set in the way native English speakers did, even though Mandarin is similar to English in the use of prosodic cues to express contrast. Our results are in line with previous studies suggesting that L2 speakers have difficulty integrating information across domains and building information structure, especially in demanding task situations like in the present study.