यो वाचि तिष्ठन्वाचोऽन्तरो यं वाङ्-न वेद यस्य वाक्शरीरं यो वाचमन्तरोयमयत्येष त आत्मान्तर्याम्यमृतः ॥ १७ ॥
In plain words
The one who lives inside every word you speak, yet is nothing speech can claim as its own, whom speech itself never knows, whose body speech is, who governs it from within -- that is your self, the ruler seated inside everything, and death does not touch him.
Close to the Sanskrit
He who, dwelling in speech, is other than speech, whom speech does not know, whose body speech is, who controls speech from within -- he is your self, the inner controller, immortal.