The distinction between representations and processes is central to most models of the cognitive science of language. Linguistic theory informs the types of representations assumed, and these representations are what are taken to be the targets of second language acquisition. Epistemologically, this is often taken to be knowledge, or knowledge-that. Techniques such as Grammaticality Judgment tasks are paradigmatic as we seek to gain insight into what a learner’s grammar looks like. Learners behave as if certain phonological, morphological, or syntactic strings (which may or may not be target-like) were well-formed. It is the task of the researcher to understand the nature of the knowledge that governs those well-formedness beliefs.
Traditional accounts of processing, on the other hand, look to the real-time use of language, either in production or perception, and invoke discussions of skill or knowledge-how. A range of experimental psycholinguistic techniques have been used to assess these skills: self-paced reading, eye-tracking, ERPs, priming, lexical decision, AXB discrimination, and the like. Such online measures can show us how we “do” language when it comes to activities such as production or comprehension.
There has long been a connection between linguistic theory and theories of processing as evidenced by the work of Berwick (The Grammatical Basis of Linguistic Performance). The task of the parser is to assign abstract structure to a phonological, morphological, or syntactic string; structure that does not come directly labeled in the acoustic input. Such processing studies as the Garden Path phenomenon have revealed that grammaticality and processability are distinct constructs.
In some models, however, the distinction between grammar and processing is less distinct. Phillips says that “parsing is grammar,” while O’Grady builds an emergentist theory with no grammar, only processing. Bayesian models of acquisition, and indeed of knowledge, assume that the grammars we set up are governed by a principle of entropy, which governs other aspects of human behavior; knowledge and skill are combined. Exemplar models view the processing of the input as a storing of all phonetic detail that is in the environment, not storing abstract categories; the categories emerge via a process of comparing exemplars.
Linguistic theory helps us to understand the processing of input to acquire new L2 representations, and the access of those representations in real time.
Throughout the 20th century, structuralist and generative linguists have argued that the study of the language system (langue, competence) must be separated from the study of language use (parole, performance), but this view of language has been called into question by usage-based linguists who have argued that the structure and organization of a speaker’s linguistic knowledge is the product of language use or performance. On this account, language is seen as a dynamic system of fluid categories and flexible constraints that are constantly restructured and reorganized under the pressure of domain-general cognitive processes that are not only involved in the use of language but also in other cognitive phenomena such as vision and (joint) attention. The general goal of usage-based linguistics is to develop a framework for the analysis of the emergence of linguistic structure and meaning.
In order to understand the dynamics of the language system, usage-based linguists study how languages evolve, both in history and language acquisition. One aspect that plays an important role in this approach is frequency of occurrence. As frequency strengthens the representation of linguistic elements in memory, it facilitates the activation and processing of words, categories, and constructions, which in turn can have long-lasting effects on the development and organization of the linguistic system. A second aspect that has been very prominent in the usage-based study of grammar concerns the relationship between lexical and structural knowledge. Since abstract representations of linguistic structure are derived from language users’ experience with concrete linguistic tokens, grammatical patterns are generally associated with particular lexical expressions.