विज्ञातं विजिज्ञास्यमविज्ञातमेत एवयत्किंच विज्ञातं वाचस्तद्रूपं वाग्घि वि-ज्ञाता वागेनं तद्भूत्वावति ॥ ८ ॥
In plain words
The known, the knowable, and the unknown—these comprise all. Whatever is known is simply a form of speech, for speech is the ultimate knower, and speech becomes that known reality to protect and sustain the seeker.
Close to the Sanskrit
The known, what is to be known, and the unknown—these indeed. Whatever is known is the form of speech; for speech is the knower, and speech having become that protects him.