A Pictorial Guide to Lingual-Palatal-Contact Patterns of /t/, /s/, /ʃ/, and /tʃ/ in Typically Developing Children Aged 3-7 Years Old.
(EPG) is used in research/clinical practice to provide information about articulatory movements of the tongue during speech. EPG research focuses on typical adult and impaired adult/child speech productions, with little research/data into typically developing children. During intervention, adult norms are used for comparison with target sounds. Studies indicate children’s motor-speech continues to develop into mid-to-late teens therefore adult norms for comparison may not be suitable. Aims: Identify typical lingual-palatal-contact patterns for the speech sounds /t/, /s/, /ʃ/, /tʃ/ for 3-7 yo. Identify if there are differences in lingual-palatal-contact patterns across age groups. Identify the level of variability of typical lingual-palatal-contact patterns for each age group. Identify if variability in typical lingual-palatal-contact patterns decreases with age. Hypotheses: There will be more variability in lingual-palatal-contact patterns in younger children. Lingual-palatal-contact patterns in younger children will differ qualitatively to older children/adult norms. This study used data from 11 typically developing children (3;08–7;01 yo) and ‘Articulate Assistant’ to produce data on typically developing lingual-palatal-contact patterns for the speech sounds; /t/, /s/, /ʃ/ and /tʃ/. Several indices were investigated; Centre of Gravity, Variability, lingual-palatal-contact pattern, where lingual-palatal-contact occurs over the whole palate/anterior region, maximum constriction, groove width, most anterior row contacted, number of rows with complete closure and duration. Lingual-palatal-contact patterns for all sounds investigated resembled adult norms disproving hypothesis 2. A general trend towards a decrease in variability for all target sounds was found supporting hypothesis 1; suggesting a maturational trend towards the development of accurate/consistent adult-like lingual-palatal-contact. Undifferentiated lingual gestures and double articulations were identified suggesting typically developing children may produce these during the early years as they refine/develop their articulations. It is suggested that to produce/distinguish between /s/ and /ʃ/ groove width is not the most important characteristic; location of constriction may be more important.