Issues in Applied Linguistics

Brain-based discussion of language has classically centered around models focused on Broca's and Wernicke's areas. Recent neurobiological research indicates that such models may be oversimplified. The present paper attempts to propose a model in which afar greater number of brain structures are involved in language functions. To demonstrate this model, three areas of the brain rarely associated with language, the anterior cingulate gyrus, the prefrontal cortex, and the basal temporal language area (fusiform gyrus) are examined. Recent neurobiological research linking these areas to language function will be reviewed to illustrate that a whole-brain view of language is both more feasible and better supported by data than the idea of a language specific brain system, such as the Wernicke-Geschwind model.

This paper presents a neurobiologically inspired model of one aspect of adult second language acquisition (SLA): procedural linguistic skill acquisition. Procedural linguistic skills are defined as the speaker/learner's implicit, unstatable knowledge regarding the formal linguistic (i.e., syntactic, phonological, and morphological) properties of the second language (L2). Unlike declarative linguistic knowledge (i.e., semantic and lexical knowledge and explicit knowledge of the L2 linguistic system), which can be readily displayed through verbal report or description, procedural linguistic skills are best demonstrated through performance. The proposed acquisition model crucially involves the neural circuitry of the neocerebellum. The neocerebellum is a brain structure which, although traditionally associated with purely motor activity, has recently been implicated in higher cognitive and, potentially, linguistic functions. The model provides for a potential unification of the competing cerebral (Ojemann, 1991 ; Loritz, 1991) and cerebellar (Rumelhart & McClelland, 1986: Sokolik, 1990) theories of linguistic function by integrating the unique contributions of both regions of the cerebral cortex (e.g., Broca's expressive speech area and the prefrontal cortex responsible for cognitive planning and monitoring functions) and regions of the cerebellum (an enormous capacity parallel processor responsible for the integration of cognitive and sensory information). The proposed model also offers a principled account of how explicit formalized grammar instruction might potentially serve as an effective metacognitive strategy for the L2 learner's acquisition of procedural linguistic skills.

From a neurobiological perspective, the present paper addresses (1) the input-intake distinction commonly made in applied linguistics, and (2) the role of selective attention in transforming input to intake. Primary emphasis is placed on a neural structure (the nucleus reticularis thalami) that appears to be essential for selective attention. The location, connections, structure, and physiology of the nucleus reticularis thalami are examined to illustrate its critical role in information processing. By orchestrating the selection and enhancement of relevant sensory input, the nucleus reticularis thalami acts as a "conductor" of neural systems involved in learning. It is argued that investigations of brain structures such as the nucleus reticularis thalami provide a more fundamental understanding of language acquisition mechanisms.

Research in L2 attrition is a relatively new enterprise which is in need of a comprehensive theory/model. This paper presents a tentative cognitive-psychological model of language attrition, which draws on information from studies in L2 attrition, neurobiology, and psychology. This is to demonstrate that a model based on consideration of the brain has the potential of providing a plausible account of the process of language attrition, as well as the process of language acquisition.