Abstract:This paper aims to look into the textual function of yes and no and find out the motivation for their employment in written narratives from a cognitivefunctional approach.English speech progresses in tone groups.In cognitive terms a tone group is seen as realizing a focus of consciousness and a number of such focuses may make up a superfocus, which constitutes a center of interest or a basiclevel topic (Chafe 1979, 1980, 1987, 1994, 2001).In identifying the textual functions of the two words we keep in view their basic meanings, their basic functions in spoken interaction and their location in narrative discourse.Our data show that as continuatives yes and no typically occur at the boundary of two centers of interest, used irreplaceably when some perturbation occurs so that more cognitive effort is called for to further the flow of information and the flow of discourse