This study examined preferences for prosodic and structural properties of infant-directed speech (IDS) in 20 infants, 11 girls and 9 boys, ages 0;11;3 to 0;13;0 (mean age 0;11;28). It was hypothesized that year-old infants would demonstrate a preference for infant-directed structure (IS) over adult-directed structure (AS) regardless of prosody, and that infants would demonstrate no preference for either infant-directed prosody (IP) or adult-directed prosody (AP) regardless of structure. Listening times to passages were compared across infants for four conditions: IS/IP; IS/AP; AS/IP; AS/AP. Results indicate a non-significant but noticeable trend toward a preference for infant-directed structure. In addition, weak correlations were found between vocabulary size and strength of preference for adult-directed prosody, and between age and strength of preference for adult-directed prosody. A non-significant but noticeable interaction was found between prosody and structure and vocabulary. Overall, infants appear to prefer listening to infant-directed structure to adult-directed structure; more advanced language learners show a stronger preference for adult-directed prosody than do their less advanced age-mates; older infants show a stronger preference for adult-directed prosody than do younger infants; and preference for infant-directed structure (but not infant-directed prosody) depends on vocabulary level.