Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 7.6.4

7.6.4

vān me vācā dīkṣatām svāhā iti dvitīyām / (soma: dīkṣaṇīyeṣṭi)

'May my speech be consecrated through speech, svāhā'—as the second;