Do children learn words better in happy speech or child-directed speech?

Abstract

The prosodic properties in child-directed speech have been reported to promote language learning. Two controversial hypotheses have been proposed to account for factors in child-directed prosody that influence learning. The Hyperarticulation Hypothesis postulates that child-directed speech highlights the important phonetic, lexical and syntactic information, which promote language acquisition. The Affect Hypothesis proposes that happy emotions expressed in child-directed speech capture children’s attention and promote language learning. This study tested the two hypotheses by examining the effect of child-directed and happy speech on word learning in young children. Nineteen typically-developing 3- to 4-year-old Cantonese-speaking children learned novel words in stories presented with adult-directed neutral speech, adult-directed happy speech, child-directed neutral speech and child-directed happy speech. Thirteen native speakers listened to the stories and rated the intensity of happy emotions and age of target audience. Children’s novel word identification accuracy did not differ following the dichotomy of adult-directed and child-directed speech but was significantly and positively correlated with the perceived degree of happiness expressed in the prosodies. Intensity of happy emotions in the prosodies correlated negatively and almost perfectly with the age of target audience. The results supported the Affect Hypotheses and explained the relationships between happy speech and child-directed speech.