Abstract
Impaired phonology is reported to be the most salient characteristic of the communication profiles of twin children. However, little is known about the phonological development of twins speaking languages other than English. This case study described the phonological systems of a set of Putonghua-speaking twins, using quantitative and qualitative measures. The analyses indicated that the phonological systems of the co-twins were not identical, though both evidenced characteristics of delayed or disordered phonological development and shared some error patterns. They comprehended both adult and their sibling's phonological forms, suggesting a dual phonological representation in their mental lexicon for some words. These results confirmed Dodd and McEvoy's (1994) research findings for English-speaking twins.