Speaking rate: The Differences between Adult-directed and Infant-directed Speech.

Abstract

In this study the Infant-directed and Adult-directed Speech (IDS and ADS) of 27 Dutch mothers of 18-month-old children was analyzed. They were instructed to tell a story to an adult and to their child according to a picture book containing seven target words that were unfamiliar to the child. Overall measurements on the whole story and measurements on the target utterances were performed. It was found that both speech rate (including pauses) and articulation rate (excluding pauses) were slower in IDS compared to ADS. Mothers paused more in IDS but they did not pause longer. Finally, it was found that mothers slowed down full utterances when introducing novel words.