Translation and validation of the Intelligibility in Context Scale into Sinhala for adolescents in Sri Lanka with cleft lip and palate.

The Intelligibility in Context Scale (ICS) is a parent-report screening tool used to measure parents' perceptions of children's functional intelligibility. This tool has been translated into over 60 languages and found to have a good reliability and validity. The purpose of the current study was to translate the ICS into Sinhala (the ICS-SIN), the main language spoken by the Sinhalese people in Sri Lanka, and to validate it with both typically developing (TD) children and children with repaired cleft lip and/or palate (CLP). The translation process followed the forward-backward-forward method. A total of 88 parents of TD children and children with CLP aged 12-15 years old (TD n = 50, CLP n = 38) completed the ICS-SIN questionnaire. Parents of TD and CLP children reported their children's speech as most intelligible to parents and least intelligible to strangers. The ICS-SIN had high internal consistency for both groups (TD α = 0.87, p < 0.05, CLP α = 0.97, p < 0.05). The ICS-SIN total scores and item scores showed significant correlations, indicating a good construct validity. TD participant group's ICS-SIN average mean scores (M = 4.88, SD = 0.29) were significantly higher compared to the CLP ICS-SIN average mean scores (M = 4.64, SD = 0.67) and varied according to gender in both groups, suggesting good discriminant validity. The ICS-SIN has overall good psychometric properties. Therefore, this tool has the potential to be used as a valid parent-rating screening tool for clinical and research purposes in Sri Lanka.