Revising expectations in real time: processing speed constrains lexical form prediction in German 8-12 year-olds.

Do children predict the lexical form of upcoming linguistic input as readily as they predict semantic features? We investigated word form prediction using the prenominal mismatch paradigm, which tests whether children experience processing costs when encountering prediction-inconsistent gender-marked articles. We also examined individual differences and whether prenominal mismatch effects reflect revision of an anticipated noun. German-speaking 8-12-year-olds self-paced through sentences that either confirmed or disconfirmed expectations about a predictable noun. In half of the items, a prediction-consistent or -inconsistent gender-marked article served as an early cue signaling whether the upcoming noun would match expectations. At the group level, there was no evidence for a prenominal mismatch effect, suggesting that under time pressure, children do not reliably pre-activate word-form information based on gender. However, processing speed predicted the presence of mismatch effects: Faster child readers showed early predictability costs pre-nominally, whereas slower child readers did not. In addition, in faster children, mismatch effects were associated with reduced integration costs at the unpredictable noun, suggesting that prenominal mismatch effects reflect a revision process, whereby children dampen their expectations for the initially predictable noun. These findings suggest that lexical prediction in middle childhood is not consistently supported in time-compressed settings, and that prenominal mismatch effects reflect the revision of an initially predicted lexical representation.