Prosody in Swedish Children with Language Impairment. Perceptual, Acoustic and Interactional Aspects

Abstract: The aim of this thesis was to explore prosodic problems in Swedish children with language impairment (LI). In the first study, 29 children with LI participated. They were assessed with an assessment procedure for prosody at the word, phrase and discourse levels, developed within this thesis. The results showed that 41% of the children had prosodic problems to some extent. In addition, reliability and validity of the newly developed assessment procedure were evaluated. The procedure was found to be sufficiently reliable and also a valid instrument to assess prosodic problems. In study II data from 25 children with LI in combination with prosodic problems as assessed by their clinician, were compared to data from 25 children with typically developing language matched to age, gender and regional dialect. Results from this study showed that the children with LI in combination with prosodic problems scored significantly lower on all aspects of prosody. Moreover, the results indicated that there were at least two subgroups of prosodic problems; one with prosodic problems related to linguistic/phonetic problems and the other with prosodic problems related to pragmatic problems. Contrast of tonal word accents was one of the most difficult prosodic features to acquire for children with LI in combination with prosodic problems. The ability to produce this contrast was investigated with perceptual as well as acoustic evaluations in study III. Both the perceptual and the acoustic evaluation verified that children with LI in combination with prosodic problems had significant problems in producing the contrasts of tonal word accents. The results also indicated that the problems are a lack of contrast rather than an overgeneralization of accent II, which has previously been suggested. Study IV is a case study of two children with prosodic problems at the discourse level. In this study it was shown that prosodic problems at the discourse level may be related to pragmatic problems. The results of this thesis have important clinical implications and implications for future research.