Critical-Period Hypothesis


Critical Period Hypothesis (CPH) refers to the biological facts for which any first language is unable to acquire after a precise age. However the facts of learning second language acquisition (SLA) contrast sharply with those of first language acquisition (FLA) for many reasons. One of which is the attainment of full linguistic competence is the birthright of all normal children, therefore adults vary widely in their ultimate level of attainment, and linguistic competence comparable to that of natives is seldom attested. CPH aims to explain the facts behind FLA and SLA which in its most concise formulation, states that there is a limited developmental period during which it is possible to acquire a language, whether it FLA or SLA at the native level. Once this developmental level of attaining language learning is passed the ability to learn language decreases.


CPH concept in the earlier linguistic era supported only one hypothesis however, later linguistics believe that earlier references to the CPH are misleading, for there are multiple hypotheses and varied formulations, each of which takes a different ontogeny on the limits of language acquisition. Smith (2007) suggests CPH as a project with multiple arguments (Smith, 2007, p. 2) and she is right because there is a need to refer varied hypotheses collectively, because, manifestly, they share the common denominator of determinism. That is, they assume a non-native end state for late language acquisition and seek explanations for this outcome in developmental factors that inevitably affect all members of the species. On the other hand Rawlins (2004) suggests that the way adults can learn best is by reflecting on what they do and what are they inspired of to speak and write.

It is indeed true what CPH suggests that there is a specified time window to learn FLA, we can prove this through several hypotheses. When cerebral functions lateralize in adults, there is a process that carries throughout the cortex a functioning of the neural substrate that through the passage of time is not fully available and is required in language learning. Lenneberg later reshaped this hypothesis and postulated that the end of the critical period is marked by ending of a state of organizational plasticity linked with lateralization of function (Birdsong, 1999, p. 3). Advancements occur in context with SLA since variations were proposed and with the closure of the critical period entailed a loss of Universal Grammar (UG), a mental faculty consisting of innately specified constraints on the possible forms that natural language grammars may take. Another postulate proposes that UG continues to be mentally represented but for various reasons is no longer available or accessible to the language learner, therefore the FLA grammar is an instantiation of UG, and one can plausibly account for at least some of the headway that learners do make in SLA.

Besides CPH, other innate learning strategies suggests that learning of language include the Subset Principle, which guides the learner to posit the most conservative grammar consistent with the linguistic input. By hypothesis, these epistemological components are the sine qua non of language acquisition; their absence essentially guarantees failure to attain native competence. Thus the Fundamental Difference Hypothesis attributes the divergent end states of early FLA and late SLA to loss of, or lack of access to, UG and associated learning principles.

As children develop into adults, their innate capability of processing linguistic input that cognitive immaturity, not cognitive maturity, is advantageous for language learning. Kids short-term memory capacity is able to extract and get hold of some initial morphemes from the linguistic input. Though there are processing limits within which children are more capable than adults, but their more available memory allows them to get more hold of the input, as compared to that of the adults who then are faced with a more difficult problem of analyzing everything at once.


FL and SL development are two different entities to acquire because they support two different underlying mechanisms, but the source responsible for the two types of development is single i.e., the memory capacity. The FLA is characterized by utilizing formal features rather than functional features, which a child is more influenced to learn through informal features and due to underdeveloped conceptual fluency a child’s ability to grasp linguistic concepts is more than a normal adult. CPH in context with learning a language has been demonstrated above by testing that the hypothesis in the initial developmental age in a second language has differential effects on the neural subsystems involved in language processing. This hypothesis is also proven in the case of consideration of studies of the development and organization of visual and auditory systems because within these systems, the nature of sensory input significantly affects the development of specific neurophysiological and behavioral processes.

Work Cited

Birdsong David, (1999) Second Language Acquisition and the Critical Period Hypothesis: Lawrence Erlbaum Associates: Mahwah, NJ.

Rawlins Jack, (2004) The Writer’s Way: Houghton Mifflin Harcourt.

Smith D. Brenda, (2007) Bridging the Gap: College Reading.

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