Critical learning period for speech acquisition and screening techniques in early detection of hearing impairment

In order to develop verbal communication skills, an infant nervous system needs sound stimuli, especially human speech, in the early and critical learning period of life. The maturation of hearing and language learning abilities of an infant is considered to be complete within the first two to three years of life. Therefore, detection of hearing impairment before the end of the critical language learning period is considered crucial if a child is expected to acquire his/her native language properly. Parents or caregivers may suspect the presence of a delay in language acquisition; however, relying only on parental awareness could cause a delay in detection of the hearing impairment. Even mild hearing loss may interfere with normal development of speech and language in infants, therefore, universal screening of infants for hearing loss as early as possible should be the goal. The purpose of this paper is to discuss the concept of the critical language learning period and its relevance to language acquisition. Furthermore, it is the aim of the paper to evaluate the available techniques for early identification of hearing impairment in general and the feasibility of the various techniques in Turkey.