A combination of vocal fo dynamic and summary features discriminates between three pragmatic categories of infant-directed speech.

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.