This thesis mainly makes a detailed and somewhat technical investigation into Saussure's concepts of difference, i.e. his difference-without-positive- terms , or opposition as he also calls, and systematicity along with other related concepts, in his discourse on language drawn mainly from the Course in General Linguistics (here after CGL). The outcomes of the research would demonstrate how difference and opposition are related, and also how systematicity is involved with the two; also how they function in the basic construction of language