Phonological development in Down syndrome

This article provides an overview of the literature on phonological development in infants and children with Down syndrome. The review is divided into four major sections: the first summarizes studies of factors that may impede normal phonological development in this population: hearing loss and abnormalities of the middle ear; anatomical and physiological features of the speech mechanism; characteristics of input; and perceptual and encoding abilities. The second section examines prelinguistic vocal development and the links between babble and speech. The third section reviews literature on phonological acquisition after the onset of meaningful speech and briefly summarizes research on speech intelligibility in Down syndrome individuals. The fourth section discusses recommendations for intervention programs aimed at improving articulation and phonology in children with Down syndrome. (C) 1997 Wiley-Liss, Inc.