Verse 3.2.4.16

athopaniṣkramyābhimantrayate | cidasi manāsīti cittaṃ vā idam mano vāganuvadati dhīrasi dakṣiṇeti dhiyā-dhiyā hyetayā manuṣyā jujyūṣantyanūkteneva prakāmodyeneva gāthābhiriva tasmādāha dhīrasīti dakṣiṇeti dakṣiṇā hyeṣā kṣatriyāsi yajñiyāsīti kṣatriyā hyeṣā yajñiyā hyeṣāditirasyubhayataḥśīrṣṇīti sa yadenayā samānaṃ sadviparyāsaṃ vadati yadaparaṃ tatpūrvaṃ karoti yatpūrvaṃ tadapara ṃ tenobhayataḥśīrṣṇī tasmādāhāditirasyubhayataḥśīrṣṇīti

Preview of English translation:

16. Having gone up to her, he (the Adhvaryu) salutes her, with the text (Vajasaneyi Samhita IV, 19), “Thou art thought, thou art the mind,”—for speech, doubtless, speaks in accordance with thought, with the mind;—“Thou art intelligence, thou art the Dakshina,”—for it is by means of their respective intelligence that people seek to make their living, either by reciting (the Veda), or by readiness of speech, or by songs: therefore he says, “Thou art intelligence;” and 'Dakshina' (gift to the priests) he calls her, because she is indeed the Dakshina;- 'Thou art supreme, thou art worthy of worship,'—for she is indeed supreme and worthy of worship;—“Thou art Aditi, the double-headed,”—inasmuch as, through her (Vac, speech), he speaks the right thing wrongly, and puts last what comes first, and first what comes last, therefore she is double-headed: that is why he says, “Thou art Aditi, the double-headed.”

For a detailled translation, including proper diacritics and footnotes, go the full English translation.