Bhashya
एवम्— स एष उद्गीथारय ॐकार , भूतादीनामुत्तरोत्त-ररसानाम् , अतिशयेन रस रसतम् , परम , परमात्मप्र-तीकत्वात् , परार्ध्य — अर्ध स्थानम् , पर च तदर्ध च परार्धम् ,तदर्हतीति परार्ध्य ,— परमात्मस्थानार्ह , परमात्मवदुपा-स्यत्वादित्यभिप्राय , अष्टम — पृथिव्यादिरससङ्ख्यायाम् ,यदुद्गीथ य उद्गीथ ॥
In plain words
Thus, this sacred syllable Om, known as the Udgitha, is the ultimate essence of all essences, the highest of the high. It stands as the supreme symbol of the Divine Self. The word 'Parardhya' signifies that it is worthy of the highest place—the very seat of the Supreme Self—and is to be adored and meditated upon just like the Supreme Self. In the ascending scale of essences starting from the earth, this Udgitha is the eighth.
Close to the Sanskrit
Thus, this Omkara called Udgitha, among the progressively higher essences of elements etc., is the supreme essence in the highest degree, because of being the symbol of the Supreme Self. 'Parardhya' means: 'ardha' is place; 'para' (supreme) and that 'ardha' (place) is 'parardha' (supreme place); that which deserves that is 'parardhya'—worthy of the place of the Supreme Self, meaning it is to be meditated upon like the Supreme Self. It is the eighth in the enumeration of the essences of earth etc., which is the Udgitha, which is the Udgitha.