The Integration of Laughter and Speech in Vocal Communication A Dynamic Systems Perspective Research Article
Research Article  |   August 1999
The Integration of Laughter and Speech in Vocal Communication
 
Author Affiliations & Notes
  • Eva E. Nwokah
    Richardson Development Center for Children Dallas, TX
  • Hui-Chin Hsu
    Department of Child and Family Development University of Georgia Athens
  • Patricia Davies
    School of Mechanical Engineering Purdue University West Lafayette, IN
  • Alan Fogel
    Department of Psychology University of Utah Salt Lake City
  • Corresponding author: e-mail: enwokah@aol.com
  • Contact author: Eva E. Nwokah, PhD, LCST, CCC-SLP, Richardson Development Center for Children, P.O. Box 835066, Richardson, TX 75083-5066.
    Contact author: Eva E. Nwokah, PhD, LCST, CCC-SLP, Richardson Development Center for Children, P.O. Box 835066, Richardson, TX 75083-5066.×
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   August 1999
The Integration of Laughter and Speech in Vocal Communication
Journal of Speech, Language, and Hearing Research, August 1999, Vol. 42, 880-894. doi:10.1044/jslhr.4204.880
History: Received November 30, 1998 , Accepted March 9, 1999
 
Journal of Speech, Language, and Hearing Research, August 1999, Vol. 42, 880-894. doi:10.1044/jslhr.4204.880
History: Received November 30, 1998; Accepted March 9, 1999

Laughter in infant-directed speech was examined in 13 mother-infant pairs to investigate the possible co-occurrence of speech and laughter. Contrary to previous findings in adult-adult social interaction, all mothers produced speech simultaneously with laughter in up to 50% of laughs. In most of these speech-laughs the onset of laugh and speech was simultaneous. Laughter occurred on both function and content words and was more likely to occur on approximately 2 words and on utterances that were statements rather than questions or exclamations. Laughter and speech are different outcomes produced from a reorganization of the same vocal/anatomical parameters. A 3rd outcome is possible in the form of speech-laughs utilizing features from both laughter and speech. In speech-laughs, the duration of the vocalization was more likely to increase, and the changes in the utterance were likely to include 1 or more of the features of vowel elongation, syllabic pulsation, breathiness, and pitch change. These findings and individual variations in the resulting vocal output are discussed from a dynamic systems perspective. It is argued that neither speech nor laughter is dominant when both are combined, but that this is a more complex vocal outcome produced with idiosyncratic flexibility within stable temporal and physiological constraints.

Acknowledgments
This research was funded in part by grants from the National Institutes of Health (RO1 HD21036) to Alan Fogel, from the National Science Foundation (BNS9022214) to Alan Fogel and Eva Nwokah, and from the National Science Foundation (REU supplement) to Eva Nwokah. Preliminary portions of this research were reported at the Society for Research in Child Development Biennial Meeting, Seattle, April 1991, and at the American Speech-Language-Hearing Association Convention, Anaheim, November 1993. Data collection was completed in the Department of Child Development and Family Studies, Purdue University. The Department of Audiology and Speech Sciences, Purdue University, assisted with hearing tests for the infants and equipment loan for part of the study. The authors are grateful for their assistance and cooperation. This study also would not have been possible without the mothers and their children who gave their time to participate. The student assistants, Julie Locklar, Yvonne Schneider, and Marcus Olsen are also acknowledged for their dedicated work.
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