Distinguishing dialect and development from disorder: case studies.

Seven case studies are presented to illustrate how the tasks in the proposed test battery provide the tools to distinguish language differences due to development or dialect from true signs of delay or disorder. The case studies exemplify different combinations of language strengths and weakness found among participants of extensive field research in the age range from 4 to 9 years. Special attention is paid to certain aspects of language development, such as time clauses or double wh-questions, in which dialect features play no role. All levels of performance, from the highest to the lowest, are found in children who are speakers of Mainstream American English (MAE) and the same is true for those whose language patterns indicate a strong variation from MAE.