The speaker talks to their own body, giving orders to the jaw, bones, lips and voice as if each part were a soldier waiting for instructions. The aim is to speak, and to do it with force. The jaw must "bend to my will," the bones must "tremble with my flesh," and the lips must speak "through my soul." Speaking here isn't casual. It feels physical and risky, something that shakes the whole body.
The mood shifts as the poem goes on. The first stanzas sound determined, almost like someone psyching themselves up. By the last one, the tone turns harsh. The speaker wants the voice to leave the listeners "brittle," to "break them first," and to "let them bleed." Judging by the language, the speaker may feel unheard or unseen, and wants the onlookers to be forced to pay attention. The poem leaves us with a mix of courage and anger, and a sense that the voice is being used as a weapon.