Let him meditate on speech as a cow. Her four udders are the words Svaha, Vashat, Hanta, and Svadha. The gods live on two of her udders, the Svaha and the Vashat, men on the Hanta, the fathers on the Svadha. The bull of that cow is breath (prana), the calf the mind.

In plain words: One should think of speech as a cow with four udders, which are four sacred words used in rituals. The gods are fed by two of them, people by one, and the ancestors by the last. Breath is the cow's bull and the mind is her calf.