तयोरन्यतरां मनसा संस्करोति ब्रह्मा वाचा होताध्वर्युरुद्गातान्यतराँ स यत्रोपाकृते प्रातरनुवाके पुरा परिधानीयाया ब्रह्मा व्यवदति ॥ २ ॥
In plain words
Of these two paths, the Brahma priest refines one with his mind, while the Hotṛ, Adhvaryu, and Udgātṛ priests refine the other with speech. After the morning recitation has begun and before the final concluding verse, the Brahma priest speaks.
Close to the Sanskrit
Of those two, the Brahma priest refines one path with the mind, the Hotṛ, Adhvaryu, and Udgātṛ priests refine the other path with speech. He, where the morning recitation has been commenced, before the concluding verse, the Brahma priest speaks.