अथाध्यात्मं वागेवर्क्प्राणः साम तदेतदेतस्यामृच्यध्यूढं साम तस्मादृच्यध्यूढंसाम गीयते ।वागेव सा प्राणोऽमस्तत्साम ॥ १.७.१ ॥
In plain words
Now with respect to the self. Speech is the Ṛc and the breath is the Sāman. This Sāman rests upon that Ṛc; therefore the Sāman is sung as resting upon the Ṛc. Speech is sā and the breath is ama, and that makes sāman.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
अथ अधुना अध्यात्ममुच्यते—वागेव ऋक् प्राण साम, अधरोपरिस्थानत्वसामान्यात् । प्राणो घ्राणमुच्यते सह वा- युना । वागेव सा प्राणोऽम इत्यादि पूर्ववत् ॥
In plain words
Now the subjective application is explained: speech itself is the Ṛk, and breath is the Sāman, because of their relative lower and upper positions. Breath here is referred to as the organ of smell, together with air. The rest—'Speech is indeed that, breath is that...'—is to be understood as before.
Close to the Sanskrit
Now the subjective (adhyātma) is explained: speech indeed is Ṛk, breath is Sāman, due to the commonality of being positioned lower and upper. Prāṇa is spoken of as the nose, along with the air. 'Speech indeed is that, breath is that...' [is interpreted] as before.