A study of obstruent sounds in school-age children with speech disorders using electropalatography

In this study EPG was used to investigate the articulatory characteristics of voiceless coronal obstruent targets /s, f, tf, t/ in ten children with functional articulation disorders. Perceptually based judgements of /s, f, tf/ revealed a variety of distortions, including palatal, lateralised and dental articulations. Their productions of /t/ were judged to be acceptable. From the EPG data, it was observed that individual children produced abnormal and often idiosyncratic tongue-palate contact for sounds which were heard as distorted. Some common trends were identified, for example, palatal fricatives and affricates were produced with constriction and a groove configuration in the posterior region of the palate. Lateralised articulations were generally associated with complete contact across the palate, increased tongue-palate contact and, for some children, incomplete lateral seal was observed. Place of articulation (as revealed by EPG) varied for coronal targets heard as lateralised. Some children produced these sounds with contact in the alveolar region, others had palatal contact and one child had contact in the velar region. These differences in place of articulation had not been identified from an auditory-based analysis. One child was heard to produce dental fricatives and affricates, and the EPG patterns were found to have an asymmetrical groove configuration in the anterior region of the palate. The clinical implications of the findings are discussed.