Which choice does NOT affect the clarity of communication?

When considering what affects the clarity of communication, the number of people present can indeed play a role. However, it is not an intrinsic factor affecting the clarity on an individual level, unlike the other options which directly relate to how a message is conveyed and interpreted.

The choice of words is fundamental to communication; specific and precise vocabulary can either enhance or hinder understanding. Using gestures can also clarify meaning, particularly when verbal communication may be inadequate. Facial expressions are key in conveying emotions and attitudes, which are crucial for contextual understanding in communication.

In contrast, while the number of people present can influence the dynamics and focus of a conversation, it does not inherently change how clear the message itself is. A conversation among many can be as clear or confusing as among few, depending largely on the other factors involved in communication. Therefore, this aspect is less about the clarity of the message itself and more about the environment and context in which it is delivered.