Production and perception of listener-oriented clear speech in child language.

In this paper, we ask whether children are sensitive to the needs of their interlocutor, and, if so, whether they - like adults - modify acoustic characteristics of their speech as part of a communicative goal. In a production task, preschoolers participated in a word learning task that favored the use of clear speech. Children produced vowels that were longer, more intense, more dispersed in the vowel space, and had a more expanded F0 range than normal speech. Two perception studies with adults showed that these acoustic differences were perceptible and were used to distinguish normal and clear speech styles. We conclude that preschoolers are sensitive to aspects of the speaker-hearer relationship calling upon them to modify their speech in ways that benefit their listener.