Dialogue is not just quotation. It is grimaces, pauses, adjustments of blouse buttons, doodles on a napkin, and crossings of legs.

Stern is emphasizing that effective dialogue—especially in fiction and drama—extends beyond the literal words spoken. Real conversation is inseparable from the physical and social “stage business” that accompanies it: facial expressions, timing, fidgeting, and small gestures that reveal power dynamics, discomfort, flirtation, boredom, or deception. By listing mundane actions (button-adjusting, doodling, leg-crossing), he points writers toward observable behavior as a carrier of subtext. The quote argues for dialogue as a composite of speech plus embodied cues, where meaning often resides in what is done, not merely what is said.