A Combination of Vocal f0 Dynamic and Summary Features Discriminates between Three Pragmatic Categories of Infant-Directed Speech


  • This research was supported by NSF grant no. BNS-8919711 to Jeffrey Cohn and Christopher Moore and NIMH grant no. MHR0140867 to Susan Campbell and Jeffrey Cohn. Portions of these data were presented at the biennial meeting of the Society for Research in Child Development in New Orleans, LA, in March 1993, and at the annual meeting of the American Speech, Language, and Hearing Association in San Antonio, TX, in November 1992. Thanks are due to Lourdes Caro-Martinez, Susan Ranier, Joan West, and Adena Zlochower for assistance with data collection and analysis and to Michael Pogue-Geile, Adena Zlochower, Anne Fernald, Robin Cooper, and anonymous reviewers for constructive suggestions at various points of the research.

concerning this article should be addressed to Gary Katz at the Department of Psychology, 604 OEH, 4015 O'Hara Street, Pittsburgh, PA 15260.


To assess the relative contribution of dynamic and summary features of vocal fundamental frequency (f0) to the statistical discrimination of pragmatic categories in infant-directed speech, 49 mothers were instructed to use their voice to get their 4-month-old baby's attention, show approval, and provide comfort. Vocal f0 from 621 tokens was extracted using a Computerized Speech Laboratory and custom software. Dynamic features were measured with convergent methods (visual judgment and quantitative modeling of f0 contour shape). Summary features were f0 mean, standard deviation, and duration. Dynamic and summary features both individually and in combination statistically discriminated between each of the pragmatic categories. Classification rates were 69% and 62% in initial and cross-validation DFAs, respectively.