Dissociations of Inflectional and Derivational Processes in Persian Deaf Individuals

The present study aims to investigate the performance of Persian deaf individuals in using nonverbal inflectional and derivational processes. Drawing upon the assumption that different components of language are not impaired to the same extent as a result of missing a critical period, the morphological knowledge of participants in the three categories of noun, adjectives, and adverbs were examined using multiple choice questions. Participants were ten deaf students aged 15-20 and a matched number of hearing students of similar age. While error scores indicated a significant gap between deaf and hearing group, a within group analysis indicated a significant difference between inflectional and derivational processes within the deaf group who were significantly worse on tasks related to inflectional processes. It is also concluded that the deaf students, due to missing the critical years of language acquisition are less skilled at using both inflectional and derivational morphology as compared to their hearing peers.