The syllable Hâu is this world (the earth), the syllable Hâi the air, the syllable Atha the moon, the syllable Iha the self, the syllable Î is Agni, fire.
The syllable Û is the sun, the syllable E is the Nihava or invocation, the syllable Auhoi is the Visve Devas, the syllable Hin is Pragâpati, Svara (tone) is breath (prâna), the syllable Yâ is food, the syllable Vâg is Virâg.
दुग्धे ऽस्मै वाग् दोहं यो वाचो दोहः । अन्नवान् अन्नादो भवति । य एताम् एवं साम्नाम् उपनिषदं वेदोपनिषदं वेद
dugdhe 'smai vāg dohaṃ yo vāco dohaḥ | annavān annādo bhavati | ya etām evaṃ sāmnām upaniṣadaṃ vedopaniṣadaṃ veda
Speech yields the milk, which is the milk of speech itself to him who knows this Upanishad (secret doctrine) of the Sâmans in this wise. He becomes rich in food, and able to eat food,—yea, able to eat food.