Articulatory drift in the speech of children with articulation and phonological disorders.

This study used electropalatography to identify articulatory drift in alveolar stops (/t/ and /d/) produced by 10 children with functional articulation and phonological disorders. Drift involves an abnormal change in place of articulation that occurs during stop closure. An index was used to measure drift, with higher values indicating greater drift. The results showed that drift was higher for children who produced undifferentiated gestures (articulations with increased tongue-palate contact). Drift is an important characteristic of articulation because it is believed to reflect impaired speech motor control. In addition, drift could explain some perceptually based speech errors that are frequently reported in functional disorders.