Based on ethnographic and linguistic analyses, this article describes the discourse-related practices and interactional role behaviours of an experienced lawyer who assumed a pivotal role in the negotiation of a Mergers-and-Acquisitions type transaction vis-a-vis a number of other legal and financial professionals. Set in an international business context, all communication took place in English and for the most part via email. Complex discursive processes facilitated close interdisciplinary engagement and, more particularly, required that a single individual assume a key interactional role (...) to oversee and advance the negotiation activities. This pivotal role entailed the strategic use of language and discourse to negotiate, account for, and justify the various stages of the negotiation. In addition to textual analyses of the negotiated contract and attendant emails, interviews were conducted with the principal lawyer and her senior partner in order to examine the textual findings grounded in the organisational context of a law firm and produce an ontology of this negotiation process. These research findings could be used to assist novice lawyers and business professionals to understand some of the discourse strategies and interactional roles that are often so critical for commercial contract negotiation activities. (shrink)