On this hypothesis, language acquisition involves filling in the details of an innate blueprint rather than being an entirely inductive process.
Arguments in favour include the poverty of the stimulus, the universality of language acquisition, as well as experimental studies on learning and learnability.
It is intended as an explanation for the fact that children are reliably able to accurately acquire enormously complex linguistic structures within a short period of time.
[5] Poverty of the stimulus arguments claim that the evidence a child receives during language acquisition is not sufficient to determine the eventual linguistic output.
However, despite the properties mentioned above, children would eventually be able to deliver a linguistic output that is similar to the target language within a relatively short amount of time.
[13][14] The critical-period hypothesis of the linguist Eric Lenneberg states that full native competence in acquiring a language can only be achieved during an optimal period.
Genie's subsequent language-acquisition process was studied, whereby her linguistic performance, cognitive and emotional development was deemed abnormal.
[21][22] The development of the Nicaraguan sign language (NSL) by students in a school for the deaf also lends evidence to the critical-period hypothesis.
Initially a pidgin sign language with simple grammar, it had large grammatical differences and variations across signers.
Eventually, the pidgin became a full-fledged language (like a creole) as younger signers developed a significantly more grammatically-structured and regular system[23] such as specific grammatical structures[24] Often, the differences in abilities between younger and older students learning to use sign language are said to suggest evidence for a critical period.
[27][28] According to Chomsky, humans are born with a set of language-learning tools referred to as the LAD (language acquisition device).
Bates and Elman summarised a research conducted by Saffran, Aslin and Newport[38] that supports that learning is "a purely inductive, statistically driven process".
Moreover, it raises the possibility that infants possess experience-dependent mechanisms that allow for word segmentation and acquisition of other aspects of language.
[40] As a result, Bates and Elman found that this contradicts the extensive view that human beings are unable and cannot utilize generalized statistical procedures for language acquisition.
Michael Tomasello's findings highlight the significance of a usage-based theory of language acquisition and indicates that there is a relation between cognitive and social skills with linguistic competence.
In addition, his experiments indicate that children's awareness and understanding of the intentional communicative cues displayed by others is a salient social cognitive skill that determines their ability to learn words.
[42] Tomasello also stated that young children's initial multi-word productions are very concrete as they are based on specific words and phrases instead of innate and abstract linguistic categories.
[45] This ability indicates that a child is equipped with the capacity for normalisation which plays a fundamental role in acquiring the phonology of a language.