Which of the following terms refers to making gestures for emphasis while speaking?

The term that refers to making gestures for emphasis while speaking is "gesticulate." This word is derived from the Latin word "gesticulatus," which means to gesture. When someone gesticulates, they use hand movements and body language to help convey their message or to emphasize points they are making while speaking. This form of communication enhances verbal messages and helps engage the audience, making the speaker's expression more vivid and dynamic.

In contrast, the other terms do not relate to gestures in a speaking context. "Glisten" refers to something shining or sparkling, typically used in a context involving light. "Gestulate" is a less common term and is often confused with "gesticulate," but it has no established meaning in public speaking. "Grapple" means to struggle or wrestle, often used in physical or metaphorical contexts, and does not pertain to the act of speaking or using gestures.

Thus, the correct answer highlights the importance of body language in effective communication and presentation skills.