Abstract:

Many hearing children from hearing parents are exposed to quality linguistic environments from birth. In contrast, however, many deaf children, born in hearing families (i.e., 90% of deaf children have hearing parents) have limited and inadequate language exposure from birth. The poor language stimulation experienced by deaf children, coupled with limited exposure to a formal written language system, escalates into major language acquisition backlogs for these children. Research results have further shown that many deaf children, due to the absence of sign language being used in hearing families, never reach their full language development potential. Consequently, adversely affecting their academic performance, whilst inadequate language exposure and communication difficulties may also lead to depression, introversion and socialization problems for many deaf children. This theoretical paper, aims to investigate the language acquisition challenges of deaf children by drawing on the applicability of the Critical Period Hypothesis (CP) for Language Acquisition on signed languages. Some theorists have proposed that the outcomes of language acquisition are not uniform over an individual's lifespan, but rather is best acquired during early childhood. Originally the CP hypothesis was formulated and proposed only for spoken or oral languages. However, in later years’ researchers also started to investigate whether the CP hypothesis is applicable to signed languages as well. Emanating from the above, this theoretical paper will explore the applicability of the CP hypothesis to signed languages by discussing two important determinants in language acquisition, namely early diagnosis of hearing loss and the effect of early intervention on deaf children's language and literacy acquisition abilities. This theoretical paper will also compare the language developmental milestones of deaf children exposed to sign language from birth to those of hearing children being exposed to spoken language from birth.

Keywords:

Critical period hypothesis, signed language, language acquisition and language development milestones.