14th International Congress of Phonetic Sciences (ICPhS-14) San Francisco, CA, USA August 1-7, 1999

Context Sensitivity of Lateralized /s/: A Developmental Study

M. Irene Stephens (1), F. Ling Lu (2), Linda Kahvazadeh (2), Charles Kruger (2), Kuen Kao (2), Ray Daniloff (2), Gordon Schuckers (3)

(1) Northern Illinois University; (2) The University of North Texas; (3) Louisiana State University Medical Center-Shreveport, LA, USA

This study examined context sensitivity of productions of lateralized /s/ spoken by five kindergarten children, who were later re-recorded in high school. LPC spectra were derived for each /s/ spectrum. Means, Standard Deviations, Skewness and Kurtosis were computed for each spectrum. A set of 3-point ratings of four “spectral fitness” measures based on idealized /s/ spectra for children and adults was made. These measures included Number of Spectral Peaks, Frequency of Spectral Peaks, Spectral Fill, and Spectrum Bandwidth. Analyses of variance of the eight measures revealed that the most facilitory (least lateralized) contexts were /u, æ, ʌ, and l/ in the pretest, with /i, k/ less facilitory. For the grown children, whose average improvement in spectral scores was nearly 40%, /u, æ, ʌ, and l/ were included amongst the most facilitating contexts, but /i, and k/ were not. Results suggest that on average many context effects are modest and not generalizable across age. Individual subjects were differentially sensitive to phonetic context. The value of the “facilitating“ contexts for lateralization may be too idiosyncratic and insufficiently potent for generalization across speakers.

Full Paper

Bibliographic reference.  Stephens, M. Irene / Lu, F. Ling / Kahvazadeh, Linda / Kruger, Charles / Kao, Kuen / Daniloff, Ray / Schuckers, Gordon (1999): "Context sensitivity of lateralized /s/: a developmental study", In ICPhS-14, 815-817.