Important Issues in Language Research

Important Issues in Language Research

From a historical standpoint, one of the earliest questions about language has pertained to the concept of cerebral dominance and differential lateralization. A second area of investigation that has gained considerable interest because of cross-disciplinary research efforts is concerned with structural and functional localization of language. Researchers are concerned with whether specific regions of the brain are specialized for specific linguistic functions, including speaking, comprehending, reading and writ-ing. Furthermore, with the growing influence of cognitive neuro-science, researchers are investigating whether specific language operations are localized in different levels of processing (e.g., phonological, orthographical, lexical, syntactic) and studying specific neural substrates associated with these processing net-works. They are also interested in studying the patterns of con-nectivity between these neural networks. A third area that con-tinues to generate great interest relates to neurodevelopmental aspects of language. Some of the questions in this area deal with the acquisition and development of language, as well as with the organization of the brain for language abilities in children.

The centrality of these issues to an understanding of language is reflected in the emergence of different models for language, which are described in greater detail in later sections. Briefly, these models can be broadly classified into traditional and current models when placed in a historical context. The tradi-tional models were essentially localizationist (Wernicke, Broca, early contributions of Geschwind); the current models are more “hybrid” (Mesulam, 1990) in that they reflect a conceptualization of language processing as being both localized and distributed

Because a great deal of what is understood about language and continues to intrigue investigators has emerged from stud-ies of deficits and their neuroanatomical correlates in the various language disorders, especially aphasia, a description of these is important and is provided next. For more detailed reviews of lan-guage disorders, the reader is referred to other sources (Benson and Geschwind, 1985; Heilman and Valenstein, 1993).