Phonologic Error Distributions in the Iowa-Nebraska Articulation Norms Project

The errors on word-initial consonant clusters made by children in the Iowa-Nebraska Articulation Norms Project (Smit, Hand, Freilinger, Bernthal, & Bird, 1990) were tabulated by age range and frequency. The error data show considerable support for Greenlee's (1974) stages in the acquisition of clusters: the youngest children show cluster reduction, somewhat older children show cluster preservation but with errors on one or more of the cluster elements, and the oldest children generally show correct production. These stages extended to three-element clusters as well. Typical cluster reduction errors were (a) reduction to the obstruent in obstruent-plus-approximant clusters and (b) reduction to the second element in /s/-clusters. When clusters were preserved, but one member was in error, the error was typically the same as for the singleton consonant. Cluster errors are discussed in terms of theories of phonologic development, including open genetic programs and feature geometry. These data are expected to be useful in evaluation and treatment of disorders of phonology.