The purposes of this longitudinal project are to explore the developmental trajectory of early receptive language abilities in preterm infants (<28 weeks gestation), to compare performance by these infants on tests of receptive abilities to that of full-term infants, and to examine how such performance may be related to measures of language outcome. Children born prematurely are at a higher risk for linguistic delays than are their age-matched counterparts. Specifically, they show impaired word stress discrimination, reduced vocabulary and phonological working memory, and deficits in pre-reading skills. However, the etiology of these linguistic deficits is unclear because most research has focused on preschool and school-aged children. The current study proposes to assess three components of receptive language abilities that have been shown to play major roles in word-learning in full-term children and in which preterm infants are likely to show deficits. The first component, prosody, will be investigated with two experiments examining ability to distinguish native- and non-native language prosodic patterns and preference for trochaic vs. iambic word stress. The second aspect, phonotactics, will be investigated with experiments examining infants'preference for high- vs. low-probability speech sound sequences in the native language. The third component, word-form representations, will be investigated with three experiments examining word-learning, mispronunciation detection, and speed of word recognition. Prosodic processing abilities, sensitivities to phonotactic patterns and ability to detect mispronunciations have all been linked with successful word segmentation and word learning in full-term infants. Results from studies at ages 2-19 months (corrected age) will be used as predictors for speed of recognition and vocabulary size at 25 months (these have been shown to be predictors of language achievement up to 8 years). Knowledge of how early lags in receptive language processing are predictive of poor language outcomes can assist in development of earlier detection and intervention protocols with at-risk infants than is now possible.