In the performance of activities in an organization, communication plays a dominant role in that it allows people to coordinate their activities. They organize their activities by having conversations intending to initiate actions and report on them. The modeling of business communication is a central part in the communication-centered organizational modeling approach called dynamic essential modeling of organizations (DEMO), and is important for specifying the behavior of participating actors in detail. According to DEMO, by performing communicative acts, we call them organization primitives, different kinds of commitments are produced and mutual obligations are established. In this paper, we elaborate on the profits of using linguistic instruments for modeling business communication. In particular, we examine how functional grammar (FG) can be used to determine the (structure of) organization primitives. To illustrate this we use some expressions extracted from an actual conversation involving a hotel reservation. In addition, we focus on the profits of using FG for requirements engineering by an exploration of the relation between FG and Conceptual Prototyping Language (CPL). For this examination, we use a requirements document concerning the reservation function of a hotel.