Communicating with people from different countries implies not only choosing the appropriate words but also using appropriate verbal and non-verbal resources in order to enhance communicative effectiveness and thus be perceived as being interactionally competent. This paper focuses on discourse markers. Discourse markers are often classified as belonging to the realm of spoken grammar (cf. McCarthy and Carter 2001), a field which still receives considerable attention in textbooks. First, the concept of grammatical interactional competence (Young 2011, Walsh 2012) is defined; second, we illustrate how discourse markers help maintain and enhance specific interpersonal and textual functions contributing to grammatical coherence in spoken interaction in keeping with relevant English language learning objectives; third, examples are provided to support this claim by analyzing listening comprehension texts taken from current textbooks. The results of the analysis indicate that: a) listening comprehension texts do in fact include discourse markers, though b) not all their functions may be included in the book; and, finally that c) listening comprehension texts can be a good way to provide contextualized examples of the correct use of certain grammatical features of spoken language and, in particular, of discourse markers which contribute to the improvement of interactional competence in students.