SB 11.21.38-40

yathorṇanābhir hṛdayād
 ūrṇām udvamate mukhāt
ākāśād ghoṣavān prāṇo
 manasā sparśa-rūpiṇā
chando-mayo ’mṛta-mayaḥ
 sahasra-padavīṁ prabhuḥ
oṁkārād vyañjita-sparśa-
 svaroṣmāntastha-bhūṣitām
vicitra-bhāṣā-vitatāṁ
 chandobhiś catur-uttaraiḥ
ananta-pārāṁ bṛhatīṁ
 sṛjaty ākṣipate svayam
Synonyms: 
yathā — just as; ūrṇa-nābhiḥ — a spider; hṛdayāt — from its heart; ūrṇām — its web; udvamate — emits; mukhāt — through its mouth; ākāśāt — from the ether; ghoṣa-vān — manifesting sound vibration; prāṇaḥ — the Lord in the form of the original life air; manasā — by means of the primeval mind; sparśa-rūpiṇā — which exhibits the forms of the different phonemes of the alphabet, beginning with the sparśa letters; chandaḥ-mayaḥ — comprising all the sacred Vedic meters; amṛta-mayaḥ — full of transcendental pleasure; sahasra-padavīm — which branches out in thousands of directions; prabhuḥ — the Supreme Personality of Godhead; oṁkārāt — from the subtle vibration oṁkāra; vyañjita — expanded; sparśa — with the consonant stops; svara — vowels; uṣma — sibilants; anta-stha — and semivowels; bhūṣitām — decorated; vicitra — variegated; bhāṣā — by verbal expressions; vitatām — elaborated; chandobhiḥ — along with the metrical arrangements; catuḥ-uttaraiḥ — each having four syllables more than the previous; ananta-pārām — limitless; bṛhatīm — the great expanse of Vedic literature; sṛjati — He creates; ākṣipate — and withdraws; svayam — Himself.
Translation: 
Just as a spider brings forth from its heart its web and emits it through its mouth, the Supreme Personality of Godhead manifests Himself as the reverberating primeval vital air, comprising all sacred Vedic meters and full of transcendental pleasure. Thus the Lord, from the ethereal sky of His heart, creates the great and limitless Vedic sound by the agency of His mind, which conceives of variegated sounds such as the sparśas. The Vedic sound branches out in thousands of directions, adorned with the different letters expanded from the syllable om: the consonants, vowels, sibilants and semivowels. The Veda is then elaborated by many verbal varieties, expressed in different meters, each having four more syllables than the previous one. Ultimately the Lord again withdraws His manifestation of Vedic sound within Himself.
Purport: 

Śrīla Śrīdhara Svāmī has given an elaborate technical explanation of these three verses, the understanding of which requires extensive linguistic knowledge of the Sanskrit language. The essential point is that transcendental knowledge is expressed through Vedic sound vibration, which is itself a manifestation of the Absolute Truth, the Personality of Godhead. Vedic sound emanates from the Supreme Lord and is vibrated to glorify and understand Him. The conclusion of all Vedic sound vibration is found in Bhagavad-gītā, wherein the Lord states, vedaiś ca sarvair aham eva vedyaḥ: all Vedic knowledge is simply meant to teach us to know and love God. One who always thinks of Lord Kṛṣṇa, who becomes the Lord’s devotee and who bows down to and worships the Lord with faith and devotion, chanting His holy name, has certainly achieved a perfect understanding of all that is indicated by the word veda (“knowledge”).