Final answer:
The verbal operant that directly serves the speaker is the mand. It is used to make requests or demands for something desired, distinguishing it from other operants like intraverbals and tacts. Effective communication requires balancing directness with diplomacy.
Step-by-step explanation:
The only verbal operant that directly serves the speaker is the mand. A mand is a type of verbal behavior that is used by a speaker to express needs or wants. In other words, when someone uses a mand, they are making a request or a demand for something that they desire. This differs from other forms of verbal operants, such as intraverbals, which involve a response to someone else's verbal behavior, and tacts, which are used to comment on or describe the environment.
Effective communication in a workplace setting involves finding the right balance between directness and diplomacy. Since a mand serves the speaker by helping them to obtain what they need or want, it can be seen as a straightforward form of communication. Yet, it is important for the speaker to also consider the nuances of their language to maintain politeness and respect, especially in a professional context.