For the last 20 years, our research has focused on children’s developing skill at processing language in real time. Adults can understand spoken language with phenomenal speed and efficiency, processing 20-30 speech sounds per second in normal conversation. As infants begin learning language one word at a time, how and when do they become "fluent listeners" able to comprehend meanings in rapid speech? In the "looking-while-listening" procedure, we are discovering how young children develop competence in understanding spoken language during their first years of life and how those skills relate to children’s later skills in language production, reading, and cognition. By learning more about how children understand spoken language, we hope to develop tools for early identification and evidence for intervention practices for children with language delays.