Ingressive substitutions: typical or atypical phonological pattern?

Children with functional phonological disorders have been said to exhibit c ertain phonological characteristics that uniquely differentiate them from t hose with normal sound development. In this paper, one such defining charac teristic was examined by considering the phonological system and subsequent treatment of a child, aged 4;5, who presented with a non-ambient ingressiv e substitution pattern. Following conventional assessment and treatment pro cedures, the child's ingressive error pattern was largely unaffected, there by motivating an alternate account of the data as a case of complementary d istribution. Specifically, ingressive substitutions occurred post-vocalical ly, but never word-initially; whereas, egressive substitutions occurred wor d-initially, but never post-vocalically. Comparisons are drawn between this and another case of an ingressive substitution pattern in functional phono logical disorders. Together, the results of these studies are considered re lative to the suggestion that there are defining characteristics of this po pulation. A general conclusion which emerges is that apparent differences b etween normal and disordered populations are traceable to performance facto rs, but do not also implicate linguistic competence.