Modifying speech to children: an acoustic study of adults’ fricatives.

Abstract

This study examines the relationship between adult perception of children’s speech and their subsequent productions to children. Twenty-two adults participated in the study. In the listen-rate-say task, first the participants heard a child’s production of a speech sound and saw a picture representing the word the child was attempting. Second, they judged the child’s accuracy using a visual analog scale (VAS). Finally, they were instructed to respond to the child by naming the image. The participants also participated in a "baseline" task in which they produced sentences that contained the target words, first in a clear speech style and then a conversational speech style. That is, for the second repetition of sentences, they were explicitly told to use a speaking style that would help a listener perceive the signal. Analysis focused on the mouse-click locations, fricative centroids and durations. Results revealed the average click location was correlated with the centroids of the fricatives being rated. The results were also not significantly different from those of Urberg-Carlson et al. (2008) even though in the present study the adults had knowledge of the target word they were rating. Within subjects ANOVA was used to examine whether centroid and duration differed between clear and conversational speaking style. Results revealed a revealed a significant main effect of fricative and style for duration. There was also a significant main effect of fricative for centroid. Hierarchical multiple regression was used to examine the relationship between the judgments of the children’s speech and the immediate model the participant provided after making the judgment. For /s/, a small, but statistically significant proportion of the variance in M1 was accounted for by the mouse click location. Mouse-click location accounted for a statistically significant proportion of the variance in duration for both /s/ and /ʃ/. This suggests that for a subset of our participants, the duration of the fricative produced in response to a child was in part mediated by the adult’s perception of that child’s production. The data also suggest that the centroids of the responses were not mediated by the adults’ perception in the same way as duration.