Vedic chant
The oral tradition of the Vedas (Śruti) consists of several pathas, "recitations" or ways of chanting the Vedic mantras. Such traditions of Vedic chant are often considered the oldest unbroken oral tradition in existence, the fixation of the Vedic texts (samhitas) as preserved dating to roughly the time of Homer (early Iron Age). UNESCO proclaimed the tradition of Vedic chant a Masterpiece of the Oral and Intangible Heritage of Humanity on November 7, 2008. Wayne Howard noted in the preface of his book, "Veda Recitation in Varanasi", "The four Vedas (Rig, Yajur, Sama and Atharva) are not 'books ' in the usual sense, though within the past hundred years each veda has appeared in several printed editions. They comprise rather tonally accented verses and hypnotic, abstruse melodies whose proper realizations demand oral instead of visual transmission. They are robbed of their essence when transferred to paper, for without the human element the innumerable nuances and fine intonations – inseparable and necessary components of all four compilations – are lost completely. The ultimate authority in Vedic matters is never the printed page but rather the few members – who are today keeping the centuries-old traditions alive." Tones. Vedic chantings use 4 tones  – "Udatta" उदात्त (middle tone), "Anudaatta" अनुदात्त (lower tone), "Svarita" स्वरित (higher tone) and "Deergha Svarita" दीर्घस्वरित (High tone extended). These are usually marked with intuitive "svara marks" – an underline for lower tone, a small vertical line above the letter for a higher tone and two vertical lines for Deergha Svarita. Pathas. The various pathas or recitation styles are designed to allow the complete and perfect memorization of the text and its pronunciation, including the Vedic pitch accent. Eleven such ways of reciting the Vedas were designed – Samhita, Pada, Krama, Jata, Maalaa, Sikha, Rekha, Dhwaja, Danda, Rathaa, Ghana, of which Ghana  is usually considered the most difficult. The students are first taught to memorize the Vedas using simpler methods like continuous recitation (samhitapatha), word by word recitation (pada patha) in which compounds (sandhi) are dissolved and krama patha (words are arranged in the pattern of ab bc cd ...); before teaching them the eight complex recitation styles. A "pathin" is a scholar who has mastered the pathas. Thus, a "ghanapaathin" has learnt the chanting of the scripture up to the advanced stage of "ghana". The Ghanapatha or the "Bell" mode of chanting is so called because the words are repeated back and  forth in a bell shape. The sonority natural to Vedic chanting is enhanced in Ghana. In Jatapatha, the words are braided together, so to speak, and recited back and forth. The samhita, pada and krama pathas can be described as the natural recitation styles or prakrutipathas. The remaining eight modes of chanting are classified as complex recitation styles or Vikrutipathas as they involve reversing of the word order. The backward chanting of words does not alter the meanings in the Vedic (Sanskrit) language. Oral transmission. Prodigious energy was expended by ancient Indian culture in ensuring that these texts were transmitted  from generation to generation with inordinate fidelity. Many forms of recitation or "pathas" were designed to aid accuracy in recitation and the transmission of the "Vedas" and other knowledge texts from one generation to the next. All hymns in each Veda were recited in this way; for example, all 1,028 hymns with 10,600 verses of the Rigveda was preserved in this way. Each text was recited in a number of ways, to ensure that the different methods of recitation acted as a cross check on the other. Pierre-Sylvain Filliozat summarizes this as follows: These extraordinary retention techniques guaranteed the  most perfect canon not just in terms of unaltered word order but also in terms of sound. That these methods have been effective, is testified to by the preservation of the most ancient Indian religious text, the "" ( BCE). Example of a text with nine words in different patas is set out below: Divine sound. The insistence on preserving pronunciation and accent as accurately as possible is related to the belief that the potency of the mantras lies in their sound when pronounced. The shakhas thus have the purpose of preserving knowledge of uttering divine sound originally cognized by the rishis . Portions of the Vedantic literature elucidate the use of sound as a spiritual tool. They assert that the entire cosmic creation began with sound: "By His utterance came the universe." (Brihadaranyaka Upanishad 1.2.4). The Vedanta-sutras add that ultimate liberation comes from sound as well (anavrittih shabdat). Katyayana likens speech to the supreme Brahman. He uses the Rigvedic verse – "Four are its horns, three its feet, two its heads, and seven its hands, roars loudly the threefold-bound bull, the great god enters mortals" (Rig-Veda, iv. 58, 3), to assert this claim. Katyayana explains that in the verse, the  four horns are the four kinds of words i.e. nouns, verbs, prepositions, and particles; its "three feet" mean the three tenses, past, present and future; the "two heads" imply the eternal and temporary words, distinguished as the "manifested" and the "manifester"; its "seven hands" are the seven case affixes; "threefold bound" is enclosed in the three organs the chest, the throat, and the head; the metaphor "bull" (vrishabha) is used to imply that it gives fruit when used with knowledge; "loudly roars" signifies uttering sound, speech or language; and in "the great god enters mortals" entails that the "great god  speech, enters the mortals. Thus, primal sound is often referred to as Shabda Brahman" or "word as The Absolute". Maitri Upanishad states: Mantras, or sacred sounds, are used to pierce through sensual, mental and intellectual levels of existence (all lower strata of consciousness) for the purpose of purification and spiritual enlightenment. "By sound vibration one becomes liberated" (Vedanta-sutra 4.22).