Modelling category goodness judgments in children with residual sound errors

ABSTRACT

This study investigates category goodness judgments of /r/ in adults and children with and without residual speech errors (RSEs) using natural speech stimuli. Thirty adults, 38 children with RSE (ages 7–16) and 35 age-matched typically developing (TD) children provided category goodness judgments on whole words, recorded from 27 child speakers, with /r/ in various phonetic environments. The salient acoustic property of /r/ – the lowered third formant (F3) – was normalized in two ways. A logistic mixed-effect model quantified the relationships between listeners’ responses and the third formant frequency, vowel context and clinical group status. Goodness judgments from the adult group showed a statistically significant interaction with the F3 parameter when compared to both child groups (p < 0.001) using both normalization methods. The RSE group did not differ significantly from the TD group in judgments of /r/. All listeners were significantly more likely to judge /r/ as correct in a front-vowel context. Our results suggest that normalized /r/ F3 is a statistically significant predictor of category goodness judgments for both adults and children, but children do not appear to make adult-like judgments. Category goodness judgments do not have a clear relationship with /r/ production abilities in children with RSE. These findings may have implications for clinical activities that include category goodness judgments in natural speech, especially for recorded productions.

KEYWORDS:

• Speech perception
• speech disorders
• speech acoustics

Acknowledgments

The authors wish to thank Jade Clark, Kelsey Douglas, Lucy Durepos, Lindsay Mullins, Kirsten Mosko, Leah Scholl and Caroline Spencer for their contributions to this research project, as well as all participants in the study.

Statement of interest

The authors report no declarations of interest. This work was partially supported by a NIH Translational R01 Grant ‘Improving clinical speech remediation with ultrasound technology’ #1R01DC013668-01 (Contact PI: Doug Whalen, mPI Suzanne Boyce) and by a Doctoral Research Grant Award from the Ohio Speech Language and Hearing Association.

Notes

¹ Although ‘omission’ was used as a perceptual category, there was acoustic evidence (changes in formant frequencies) for the /r/ segment in all stimuli.

² Owing to the shorter duration of most prevocalic /r/ productions, the entire acoustic record was often 20 ms, and this was used as the measurement for prevocalic /r/ tokens.

³ There was no significant effect from clinical experience on adult category goodness judgments, as determined in a preliminary analysis that included clinical experience as a predictor variable (Estimate=0.254, Std. Error=0.265, p>.338) along with the acoustic parameter. Therefore, all subsequent analyses did not include clinical experience as a factor.

Additional information

Funding

This work was supported by the National Institutes of Health [#1R01DC013668-01].