Theories of second-language acquisition

While the orientation of each research strand is distinct, they are in common in that they can guide us to find helpful condition to facilitate successful language learning.

[1] However, there are two publications in particular that are seen as instrumental to the development of the modern study of SLA: (1) Corder's 1967 essay The Significance of Learners' Errors, and (2) Selinker's 1972 article Interlanguage.

[2] In the 1970s the general trend in SLA was for research exploring the ideas of Corder and Selinker, and refuting behaviorist theories of language acquisition.

Furthermore, sociocultural theory, which explains SLA in terms of the learner's social environment, and approaches influenced by complexity science were introduced during this period.

Scholars like VanPatten and Benati have noted that this division is unlikely to change in the near future, given the strong support both areas receive from the broader fields of linguistics and psychology, respectively.

[2] These hypotheses collectively belong to early cognitive approaches to SLA, emphasizing the importance of input, output, and learner interaction in the acquisition process.

This has been criticized on the basis that there is no clear definition of i+1, and that factors other than structural difficulty (such as interest or presentation) can affect whether input is actually turned into intake.

The concept has been quantified, however, in vocabulary acquisition research; Nation reviews various studies which indicate that about 98% of the words in running text should be previously known in order for extensive reading to be effective.

In addition, Krashen (1982)’s Affective Filter Hypothesis holds that the acquisition of a second language is halted if the learner has a high degree of anxiety when receiving input.

Richard Schmidt states that although explicit metalinguistic knowledge of a language is not always essential for acquisition, the learner must be aware of L2 input in order to gain from it.

In the field of cognitive psychology, Anderson expounds a model of skill acquisition, according to which persons use procedures to apply their declarative knowledge about a subject in order to solve problems.

Under the influence of the Minimalist Program, more extensive and precise hypotheses are being generated, focusing on questions such as the initial state of interlanguage, which features are more difficult or easier to acquire, and the ultimate attainment of a second language.

Adult learners are believed to have lost access to UG, which explains the persistent errors and slower progress often observed in L2 learning compared to L1 acquisition.

Support for the FDH comes from studies showing qualitative differences between child and adult language learning, particularly in areas such as syntax and morphology.

Critics argue, however, that advanced L2 learners can achieve near-native proficiency, suggesting that UG may still play a role, albeit indirectly, in adult L2 acquisition.

Instead, learners' early attempts at producing language result in what has been described as "wild grammars," characterized by unstructured and inconsistent patterns that do not align with linguistic principles observed in L1 acquisition.

[15] Critics of this hypothesis argue that even early interlanguage grammars exhibit UG-driven systematicity, as learners gradually refine their linguistic systems through exposure to the target language.

These uninterpretable features are syntactic elements that serve a grammatical function but lack semantic meaning, such as agreement, tense, or case markers.

While UG may facilitate the acquisition of core syntactic structures, learners often struggle with interface phenomena that require the integration of multiple linguistic modules.

Slabakova[23] argues that while functional morphology is the bottleneck, other aspects of language acquisition, such as syntax and semantics, are comparatively easier to acquire because they involve structures or features that are interpretable and more directly tied to meaning.

For instance, Newport (1990) extended the argument of critical period hypothesis by pointing to a possibility that when a learner is exposed to an L2 might also contribute to their second language acquisition.

MacWhinney, Bates, and Kliegl found that speakers of English, German, and Italian showed varying patterns in identifying the subjects of transitive sentences containing more than one noun.

Some theorists and researchers have contributed to the cognitive approach to second-language acquisition by increasing understanding of the ways L2 learners restructure their interlanguage knowledge systems to be in greater conformity to L2 structures.

This model is consistent with a distinction made in general cognitive science between the storage and retrieval of facts, on the one hand, and understanding of how to carry out operations, on the other.

On the other hand, explicit knowledge involves conscious understanding of grammatical rules and structures, primarily acquired through formal education and learning.

For example, Ellis (2005) argues that conscious attention and explicit knowledge facilitate the formation of pattern recognizers, which serve as a foundation for implicit learning.

[32] Kim and Godfroid (2023) also demonstrated that implicit and explicit knowledge influence each other reciprocally, with the nature of their interaction being shaped by learning environments and task characteristics.

[33] Moreover, Dienes and Perner (2001)[34] and Williams (2005)[35] suggest that learners' unconscious implicit knowledge can later prompt conscious noticing and the formation of explicit rules.

However, the theory incorporated into SLA by Larsen-Freeman and Cameron[40] has been criticized for several reasons: the lack of evidence demonstrating its consistency with actual data, its deviation from the original complex systems theory by entirely excluding mathematical formalization, its disregard for the stability of linguistic knowledge, and its failure to distinguish between systematic error and random error due to an overemphasis on complexity.

These approaches highlight that language emerges from general cognitive processes such as pattern recognition, categorization, and analogical reasoning, rather than relying on an innate universal grammar.