The works of Ādi Śaṅkarācārya

Bṛhadāraṇyakopaniṣadbhāṣyam

Verse 25

तस्या एष पतिस्तेस्मादु ब्रह्मणस्पतिः ॥

In plain words

Of that speech prāṇa is the lord; therefore indeed he is Brahmaṇaspati.

Close to the Sanskrit

Of that this one is the lord, therefore indeed Brahmaṇaspati.