Bhashya
स वै वाचमेव प्रथमामत्यवहत्— स प्राणः, वाचमेव, प्रथमां प्रधानामित्येतत्—उद्गीथकर्मणीतरकरणापेक्षया साध-
In plain words
What is the nature of her pre-eminence? He carried her across first, performing that transport. What form does she assume after being carried across and leaving death behind? That speech, at the very time she spontaneously shook off death and limitation, became fire. Even before this, she was essentially fire, and upon parting from death she remains fire still. Yet there is this distinction: this fire now shines on the far side of death. Before liberation, bound by death in the form of individual speech, it was not luminous as it is now. Now, freed from death, it shines in its own unhindered splendor.
Close to the Sanskrit
What is that supremacy of hers?—He carried her first across, performing the carrying. What is the form of her, who has been carried across and has transcended death, is spoken of—that speech, when at which time she was freed from sin and death, transcending and being liberated spontaneously, then she became fire—that speech, being fire even previously, became fire indeed even upon separation from death. But this is the difference upon separation from death: this fire, having crossed over, shines beyond death, further than death; prior to liberation, fettered by death in the form of the individual speech-self, it was not luminous like now; now, however, it shines beyond death due to the separation from death.