Twenty Japanese-speaking twenty-six- to twenty-seven-year-old women were recorded as they conversed with an infant, an elder, or another young adult. When their utterances were acoustically compared among the three settings with regard to prosodic characteristics, elevated pitch and increased pitch range were found when their speech was directed to both the infant and the elder as compared to when it was directed to the young adult. The degree to which such modifications occurred was greater in those women who were experienced with children than in those women who were not experienced. Moreover, the degree of the modification showed a highly positive correlation in each participant when the speech was directed to the infant and when it was directed to the elder. Prosodic modifications of speech styles to infants and to elders are both exaggerated consistently through the experience with children.