Developing a weighted measure of speech sound accuracy.
OBJECTIVE
To develop a system for numerically quantifying a speaker's phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, the authors describe a system for differentially weighting speech sound errors on the basis of various levels of phonetic accuracy using a Weighted Speech Sound Accuracy (WSSA) score. The authors then evaluate the reliability and validity of this measure.


METHODS
Phonetic transcriptions were analyzed from several samples of child speech, including preschoolers and young adolescents with and without speech sound disorders and typically developing toddlers. The new measure of phonetic accuracy was validated against existing measures, was used to discriminate typical and disordered speech production, and was evaluated to examine sensitivity to changes in phonetic accuracy over time. Reliability between transcribers and consistency of scores among different word sets and testing points are compared.


RESULTS
Initial psychometric data indicate that WSSA scores correlate with other measures of phonetic accuracy as well as listeners' judgments of the severity of a child's speech disorder. The measure separates children with and without speech sound disorders and captures growth in phonetic accuracy in toddlers' speech over time. The measure correlates highly across transcribers, word lists, and testing points.


CONCLUSIONS
Results provide preliminary support for the WSSA as a valid and reliable measure of phonetic accuracy in children's speech.
Preston
Jonathan L
JL
Haskins Laboratories, 300 George St., Suite 900, New Haven, CT 06511, USA. preston@haskins.yale.edu
Ramsdell
Heather L
HL
Oller
D Kimbrough
DK
Edwards
Mary Louise
ML
Tobin
Stephen J
SJ
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D006801:Humans; D010700:Phonetics; D011571:Psychoacoustics; D015203:Reproducibility of Results; D013064:Speech Disorders / Q000175:diagnosis*; D013068:Speech Production Measurement / Q000379:methods* / Q000592:standards*; D014825:Vocabulary