Bhashya
दुग्धेऽस्मै वाग्दोहमित्याद्युक्तार्थम् ।य एतामेव यथोक्तलक्षणां साम्नां सामावयवस्तोभाक्षरविषयाम् उपनिषदं दर्शनंवेद, तस्य एतद्यथोक्तं फलमित्यर्थः ।द्विरभ्यास अध्यायपरिसमाप्त्यर्थः ।सामावयवविषयोपासनाविशेषपरिसमाप्त्यर्थइति-शब्द इति ॥
In plain words
The meaning of the passage beginning with 'Speech yields its milk...' is clear. Whoever understands this secret doctrine of the Samans—focused on the stobha syllables that form parts of the chants—receives the fruit just described. The repetition of the word 'veda' at the end marks the conclusion of the chapter and the completion of this specific meditation on the parts of the Samans. Thus ends the section.
Close to the Sanskrit
The passage beginning with 'dugdhe 'smai vāgdoham' has its meaning explained. Whoever knows this secret doctrine of the samans having the characteristics mentioned before, concerning the stobha syllables which are parts of the samans, of him this is the previously stated fruit—this is the meaning. The double repetition is for the purpose of concluding the chapter and for concluding the particular meditation concerning the parts of the samans, thus is the word 'iti'.