Acoustic indicators of articulatory organization in babbling and early speech

Date of Completion

January 2005


Health Sciences, Speech Pathology|Health Sciences, Human Development




Thirty subjects, ranging in age from 6 to 27 months were divided into three groups based on language level. Digital recordings of bV and dV babbled and true word productions were collected. Acoustic parameters analyzed included (a) durational variability (b) F1 transition slope and (c) F2 transition slope coefficients at 50 and 100 ms vowel duration. Data were analyzed for group differences in timing variability (i.e., rhythmicity) and F1 and F2 transition slope coefficients to evaluate the main contentions of the Frame-Content Hypothesis (Davis & MacNeilage, 1995a;1995b; MacNeilage & Davis, 1990; 1993; MacNeilage & Davis, 1993). No significant results were noted between the groups for timing variability measures, indicating no change in the rhythmicity of articulatory movement. Comparisons of F1 and F2 transition slope coefficients did not support a predominance of mandibular movement (or an articulatory "frame") during babbling nor a change in mandibular predominance across the language levels. Comparisons of F1 and F2 transition slope coefficients across language levels did offer empirical support for a change articulatory organization with the addition of linguistic or content elements. An additional set of analyses were conducted correlating acoustic and phonetic parameters, but indicated no significant predictive value in relating these measures during babbling and early speech development. ^