The Hindu vedic texts are tied to actual practice of the worship (yajna) and is preserved with the various actions associated with the worship. But more than this, linguists have determined from the phonetics that the vedic chants have been preserved unchanged since 1000 BCE and is a gold mine for understanding the linguistic evolution of Indo-European language group.
Vedic chant - Wikipedia
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.
[3]
Pierre-Sylvain Filliozat summarizes this as follows:
[7]
- Samhita-patha: continuous recitation of Sanskrit words bound by the phonetic rules of euphonic combination;
- Pada-patha: a recitation marked by a conscious pause after every word, and after any special grammatical codes embedded inside the text; this method suppresses euphonic combination and restores each word in its original intended form;
- Krama-patha: a step-by-step recitation where euphonically-combined words are paired successively and sequentially and then recited; for example, a hymn "word1 word2 word3 word4 ...", would be recited as "word1word2 word2word3 word3word4 ..."; this method to verify accuracy is credited to Vedic sages Gargya and Sakalya in the Hindu tradition and mentioned by the ancient Sanskrit grammarian Panini (dated to pre-Buddhism period);
- Krama-patha modified: the same step-by-step recitation as above, but without euphonic-combinations (or free form of each word); this method to verify accuracy is credited to Vedic sages Babhravya and Galava in the Hindu tradition, and is also mentioned by the ancient Sanskrit grammarian Panini;
- Jata-pāṭha, dhvaja-pāṭha and ghana-pāṭha are methods of recitation of a text and its oral transmission that developed after 5th century BCE, that is after the start of Buddhism and Jainism; these methods use more complicated rules of combination and were less used.
These extraordinary retention techniques guaranteed the most perfect canon not just in terms of unaltered word order but also in terms of sound.
[8] That these methods have been effective, is testified to by the preservation of the most ancient Indian religious text, the
Ṛgveda (
ca. 1500 BCE).
[7]
The effort to preserve the Vedas exactly leads to a very early development of linguistics and grammar in India.
Vyākaraṇa - Wikipedia
Pāṇini - Wikipedia
In conclusion, one can preserve oral tradition exactly for thousands of years if a significant fraction of a civilizations religious, cultural and technological resources are invested in such an endeavor.