This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Understanding how humans comprehend speech is an unsolved and challenging problem, in part because of the many-to-many mapping between the acoustical properties of the speech signal (i.e., frequency, timing, and amplitude) and the words perceived by the listener. The focus of this research is on the contributions of voice pitch, loudness, and speech rate (collectively termed prosody) to understanding spoken words. Previously, these prosodic aspects of the speech signal have been assumed to play a minor role in spoken word recognition, word segmentation, and lexical access. However, recent results suggest that speech prosody can have very significant effects on how words are understood. This research holds potential for significant advancements in human health, technology, and science. For example, perception or production of voice pitch, loudness, and/or speech timing are often highly disrupted in many disorders affecting speech and language, including dyslexia, autism, stuttering, Parkinson's disease, aphasia, and dysarthria. The proposed research may lead to new insights regarding mechanisms underlying these disorders, which will inform the development of better treatments for those afflicted. In addition, the research has potential to lead to improved speech technology applications, from enhanced automatic speech recognition by computer, to more natural-sounding computer-generated speech. The work provides research experiences for students at the high school, undergraduate and graduate levels.