Not much is written about the subject of silence in oratory. We usually think of the words as the important thing. But, as even the most jobbing after-dinner speaker knows, the spaces between words help to give rhythmic power and emphasis to those words. You pause for applause. You pause for effect. You pause to let something sink in.

Yet there is something that goes beyond a gap in the words. The pause into which laughter or applause flows warmly is one thing. But the longer silence — a silence that is more of a chasm than a gap — has a different purpose: it does not invite and accommodate the audience, but discomfits and even confronts them.

Such a chasm was present in the remarkable speech Emma González, a survivor of the Marjory Stoneman Douglas High School shooting, delivered to the March For Our Lives rally on Saturday in Washington. Miss González started her speech with a bald statement, urgent, flat and without preliminaries: “Six minutes and about twenty seconds.”