From LCT to Power Trio - The Cooperation Between SFL and Sociology

Over the past decade, systemic functional linguistics and Legitimation Code Theory (LCT) has been cooperating to offer insight into education, especially knowledge building. In the special issue of Linguistics and Education in 2013, Karl Maton highlights the significance of semantic waves in knowledge building. These semantic waves involve recurrent movements in the semantic gravity and semantic density. Based on this theory, considering the technicality and abstractness of high stake reading and writing expected from students, the functional linguist J. R. Martin put forward the practical concepts of power trio, including power words, power grammar and power composition as tools for teachers to use for purposes of knowledge building from the perspective of lexicon, clause and discourse. In this paper, specific attention is first paid to introduce the development of LCT to power trio. Finally, the paper will move on to raise important issues regarding the problems lies in the theories.