This paper illustrates how a freely available online corpus has been exploited in a module on teaching business letters covering the following four speech acts (functions) commonly found in business letters: invitations, requests, complaints and refusals. It is proposed that different strategies are required for teaching potentially non-face-threatening (invitations, requests) and face-threatening (complaints, refusals) speech acts. The hands-on pedagogic activities follow the "guided inductive approach" advocated by Johansson (2009) and draw on practices and strategies covered in the literature on using corpora in language learning and teaching, viz. the need for "pedagogic mediation", and the "noticing" hypothesis from second language acquisition studies.