Assessing Vietnamese children's intelligibility and speech sounds

Objective: To outline new tools and data for assessing Vietnamese children’s intelligibility and speech sounds Background: Vietnamese is one of the 20 most commonly spoken languages throughout the world and is one of the most commonly spoken home languages in many countries. The speech therapy profession is emerging in Vietnam and newly validated assessment tools and normative data are needed to support professionals working with Vietnamese-speaking children.Method: The Vietnamese translation of the Intelligibility in Context Scale (ICS-VN, McLeod, Harrison, & McCormack, 2012) was validated with 181 preschool children living in Ha Noi, Viet Nam. Similarly, the Vietnamese Speech Assessment (VSA, Phạm, Le, & McLeod, 2016) was normed with 195 typically developing preschool children living in Ha Noi and Hai Phong, Viet Nam.Results:Intelligibility in Context Scale-VN: The overall mean ICS-VN score was 4.43 (out of a maximum of 5)indicating that the Vietnamese preschoolers were usually to always intelligible. Children were more intelligible to their parents and less intelligible to strangers. The ICS-VN had good psychometric properties,with high internal reliability (α = 0.94), moderate to high correlations between items (range r = .54 to r= .80, ps < .001), and positive correlations (r = .38, p < .01) between the ICS-VN mean scores and participants’ percentage of consonants correct on the VSA. The scores on ICS-VN differed between children who had parental concerns about speech and language versus no parental concerns. Three factors affected participants’ mean ICS-VN scores: age (older children had a higher score), parents’occupation (parents who had a higher rank of occupation had a higher score), and mothers’ education level (mothers who had a higher educational level had a higher score). There was no effect for sex and fathers’ educational level.Vietnamese Speech Assessment: Children’s accuracy of accuracy of consonants, semivowels, vowels,and tones increased over time. When children were 2;0-2;5 their percentage of consonants correct (PCC)was 46.39; whereas, by 5;6-5;11, their PCC was 93.13 and the following consonants /ɲ, s, z, x/ were the most difficult consonants. Percentage of semivowels correct (PSVC) increased from 70.74 at 2 years to 99.60 at 5 years. Percentage of vowels correct (PVC) increased from 91.93 at 2 years to 98.11 at 5 years.Finally, percentage of tones correct (PTC) increased from 91.05 at 2 years to 96.65 at 5 years. The youngest children had acquired tones 1, 2, 5, and 6; whereas, the oldest age group had not acquired tone 3 (creaky thanh ngã) and tone 4 (dipping-rising thanh hỏi) at the 90% criterion.Discussion: This research of Northern Vietnamese children’s speech acquisition presents the first step towards providing validated assessments with normative data to support the emerging speech therapy profession in Viet Nam.