A Study of Ideology in Speech from the Perspective of Systemic-Functional Grammar——A case study of CDA

Critical Discourse Analysis(CDA),theoretically and practically based on Systemic-Functional Grammar(SFG) proposed by M.A.K.Halliday,regards language as a kind of social practice and an inseparable part of social construction among which ideology serves as an indispensable part.In most political speech,the politician's purpose is not to provide information for the audience but persuade — to subject the common public to certain ideologies which are usually coded implicitly behind the overt propositions.In Abraham Lincoln's Address at Gettysburg,on different language scales underlies many ideologies supposed to impose on the audience.This paper attempts to explore them from different language structures by adopting some theories in SFG.