When Jackson sees that his audience's attention is lagging a bit, he raises the intensity and volume of his voice to emphasize a series of points. Jackson then lowers his volume a bit to a more comfortable level for the audience, but occasionally accentuates important information in the same way. In response to his audience, Jackson is adjusting which aspect of his vocal delivery?
▸ rate
▸ force
▸ articulation
▸ pronunciation