Bhashya
विज्ञातं विजिज्ञास्यम् अविज्ञातम् एत एव ; तत्र विशेषःयत्किंच विज्ञातं विस्पष्टं ज्ञातं वाचस्तद्रूपम् ; तत्र स्वयमेवहेतुमाह— वाक् हि विज्ञाता, प्रकाशात्मकत्वात् ; कथमवि-ज्ञाता भवेत् या अन्यानपि विज्ञापयति ; 'वाचैव सम्रा-ड्बन्धुः प्रज्ञायते' इति हि वक्ष्यति ।वाग्विषेशविद् इदंफलमुच्यते—वागेव एनं यथोक्तवाग्विभूतिविदं तत् विज्ञातंभूत्वा अवति पालयति, विज्ञातरूपेणैवाम्यान्नं भोज्यतांप्रतिपद्यत इत्यर्थः ॥
In plain words
Everything we encounter falls into three realms: the known, the to-be-known, and the unknown. Here is the distinction: whatever is clearly known is a form of speech. The scripture itself explains why: speech is inherently known because its very nature is to illuminate. How could that which makes all other things known ever remain unknown? As the scripture will say later, 'By speech alone, O Emperor, is a friend recognized.' For one who understands this deep nature of speech, this is the reward: speech itself becomes the known universe to protect and sustain them. It means that whatever is known becomes their nourishment.
Close to the Sanskrit
The known, the to-be-known, and the unknown—these three are indeed those. There, the distinction is: whatever is known, clearly understood, that is a form of speech. There, the scripture itself states the reason: 'For speech is indeed known, because of its self-luminous nature; how could it be unknown, which makes even other things known?' For the scripture will say later, 'By speech alone, O Emperor, a helper is known.' For one who knows this specific nature of speech, this result is declared: Speech itself, becoming that known, protects him who knows the glory of speech as described, meaning that it becomes food for him precisely in the form of the known.