ABSTRACT
This chapter introduces ideas from the Legitimation Code Theory dimension of ‘Semantics’ that have been influential in shaping research into academic discourse and theory in systemic functional linguistics (SFL). The concepts of ‘semantic gravity’ and ‘semantic density’ explore the context-dependence and complexity of meanings. These concepts have been used widely by applied systemic linguists in research into education and beyond. They have also helped spur theoretical development in the framework of SFL – specifically Martin’s meta-concepts of ‘mass’ and ‘presence’. This chapter is an introduction to the concepts and illustration of how they are being used in research into accessing academic discourse. It begins by briefly highlighting how LCT concepts attend to two key obstacles to supporting knowledge-building: knowledge-blindness and shallow theorizing. Second, the key concepts are defined. Third, the chapter demonstrates how these LCT concepts are being used to explore education, drawing on studies of student assessments and teaching practice. These analyses suggest that ‘semantic waves’, where knowledge is transformed between relatively decontextualized, condensed meanings and context-dependent, simplified meanings, are the key to student achievement and enabling knowledge-building in teaching practice. How these concepts are being widely used to explore organizing principles of diverse practices in education beyond classrooms, including research and curriculum, is discussed, revealing the widespread, complex and suggestive nature of ‘semantic waves’ and their implications for understanding how to promote access to academic discourse.
