In the absence of specific intervention, children with permanent congenital hearing impairment (PCHI) typically will experience delayed or disordered speech and language abilities, with consequential impact upon their educational achievement. The potential for intervention to ameliorate the negative effects of PCHI has long been proposed to be related to the age at which hearing loss is detected and intervention is commenced. In large part, this proposition is based on the premise that there is a critical (or at least, "sensitive") period for the development of linguistic abilities-particularly phonological perception and speech discrimination abilities. It has been argued that the finite plasticity of the nervous system in very young infants means that there is a limited window of opportunity for development and organization of the auditory system. In this context, screening for PCHI in newborns presents the opportunity to provide the best possible circumstances for ensuring effective intervention and subsequent development.