Intelligibility/Severity Measurements of Prekindergarten Children’s Speech

Abstract

Intelligibility/severity measurements were obtained for 48 prekindergarten children with varying levels of phonological proficiency/deficiency. The measure used as the "standard" was percentage of words understood (i.e., orthographically transcribed correctly) in continuous speech in a known context by unfamiliar trained listeners. The children were divided into four groups based on the percentage of words understood from their continuous speech samples. The ranges of intelligibility for each group were: (a) 91–100% for children with "adult-like" speech; (b) 83–90% for children in the "mild" category; (c) 68–81% for children with moderate intelligibility/speech involvement; and (d) 16–63% for the 12 children in the "severe" (i.e., least intelligible) category. When the percentages of the children in the severe group were excluded, the range of the top three groups combined was 68–100% and the mean was 85%. For a child 4 years of age or older, any percentage of words understood in connected speech that falls below 66% (2 standard deviations below the mean) may be a potential indicator of speech difficulty. In addition, data were obtained from the 48 children to determine the correlations between the standard measure and the following intelligibility/severity measures: (a) imitated sentences, (b) imitated words, (c) listener ratings of intelligibility, and (d) phonological deviation averages. All five measures, including the standard measure, investigated in this study were strongly intercorrelated. Multiple regression analysis results yielded a prediction model that included listener ratings and imitated sentences measures. Results of multivariate analysis of variance (MANOVA), univariate analysis, and post-hoc Bonferroni tests indicated that differences between all pairs of groups were significant for the listener rating measure based on the continuous speech sample. For the percentage of words understood in continuous speech samples, the differences between all pairs of groups, except between the adult-like and mild groups, were also significant. The only group that differed significantly from the other three groups for all five measures was the severe group.