PROJECT SUMMARY Access to high-quality auditory input is crucial for successful speech and language development. Hearing losses caused by Auditory Neuropathy (AN) or Cochlear Hearing Loss (C-HL) degrade the auditory signal, but in different ways. After accounting for audibility, listeners with C-HL often exhibit normal or near-normal temporal resolution accompanied by impaired spectral resolution. Many listeners with AN display poor temporal resolution. This is important because differences in a listener’s access to timing and frequency cues can affect sensitivity to acoustic-phonetic cues that support both language acquisition and speech perception. The proposed research will evaluate the short-term and long-term effects of degraded spectral and temporal resolution on speech perception and phonological awareness in children with AN and C-HL compared to children with normal hearing. Evaluation will involve psychophysical tests of spectral and temporal resolution as well as speech perception for words in which recognition relies on either vowel or consonant perception. The training plan outlined in this fellowship proposal includes skill development in the areas of research design, signal detection, speech perception, language development, statistical modeling, professional network development, and ethical conduct of research. The combined resources of The University of North Carolina and Boys Town National Research Hospital provide unique opportunities for technical training and career development, in addition to unparalleled models of the successful integration of clinical and research endeavors.