November 16, 2016

Validation of the Intelligibility in Context Scale for Jamaican Creole-speaking preschoolers

The following article has just been accepted for publication:
Washington, K. N., McDonald, M. M., McLeod, S., Crowe, K., & Devonish, H. (2016, in press November). Validation of the Intelligibility in Context Scale for Jamaican Creole-speaking preschoolers. American Journal of Speech-Language Pathology.

Within the acceptance letter, the editor wrote: "I am quite excited to see manuscripts on languages such as this being submitted (and published) in AJSLP because these illustrate the beauty of language variation but also the challenges that such variation presents for practicing clinicians.  I believe that this contribution will be of great interest to the readership."
Here is the abstract
Purpose: To describe validation of the Intelligibility in Context Scale (ICS; McLeod et al., 2012a) and ICS-Jamaican Creole (ICS-JC; McLeod et al., 2012b; Washington & Devonish Trans.) in a sample of typically-developing 3-to-6-year-old Jamaicans.
Method: One-hundred and forty-five preschooler-parent dyads participated. Parents completed the 7-item ICS (n=145) and ICS-JC (n=98) to rate children’s speech intelligibility (5-point scale) across communication-partners (parents, immediate-family, extended-family, friends, acquaintances, strangers). Preschoolers completed the Diagnostic Evaluation of Articulation and Phonology (DEAP; Dodd et al., 2006) in English and JC to establish speech-sound competency. For this sample, we examined validity and reliability (inter-rater, test-rest, internal-consistency) evidence using measures of speech-sound production: (1) percentage-of-consonants-correct (PCC); (2) percentage-of-vowels-correct (PVC); and (3) percentage-of-phonemes-correct (PPC).
Results: ICS and ICS-JC ratings showed preschoolers were always-(5) to usually-(4) understood across communication-partners (ICS-mean=4.43; ICS-JC mean=4.50). Both tools demonstrated excellent internal consistency (α=.91), high inter-rater and test-retest reliability. Significant correlations between the two tools and between each measure and language-specific PCC, PVC, and PPC provided/demonstrated criterion-validity evidence. A positive correlation between the ICS and age further strengthened validity evidence for that measure.
Conclusions: Both tools show promising evidence of reliability and validity in describing functional speech-intelligibility for this group of typically-developing Jamaican preschoolers.