The Oral transmission and the writing of the Pali Canon:
When people hear that the Buddhist scriptures were orally transmitted for several centuries they assume that they must be very unreliable. It is often said that the Tipitaka was first committed to writing in Sri Lanka in about 100 BCE but this is a misunderstanding. The source of this information is the ancient Sri Lankan chronicle the Mahavamsa. But all this chronicle says is that the Tipitaka was first written in Sri Lanka at that time. It may well have been written down much earlier in India and indeed there is good reason to believe it was. It is likely that this was done during the reign of King Asoka. This king was a devout Buddhist, he was very concerned that the Dhamma should be preserved and disseminated, and he made wide use of writing as a part of public policy. Everything we know about Asoka suggests that committing the Tipitaka to writing is the very thing he would have done. If this is correct it would mean that about 200 years passed between the writing of the Tipitaka and the Buddha’s passing. However, the Manjusrimulakalpa says the Tipitaka was written down during the reign of Udayin, the son of King Ajatasatu (tadetat pravacanam sastu likhapayisyati vistaram). If this is correct, it would mean that the Tipitaka was written down only after the Buddha, when people who met the Buddha were still alive.
Centuries before the Buddha the brahmans, the hereditary priests of Hinduism, had perfected ways of committing the Vedas, the sacred scriptures, to memory so they could be passed on to the next generation. The earliest Vedas date from about 1500 BCE and did not start being written until at least the 11th or 12th century CE. This means that they were orally transmitted for at least 2500 years. Despite this, all historians and Indologists agree that the Vedas reflect daily life, beliefs and language of the time they were composed, i.e. that they have been faithfully handed down. How was this done? A brahman’s whole life was dedicated to becoming a living receptacle for the Vedas. From an early age they chanted them until they had committed them to memory, great attention was given to getting pronunciation and intonation correct. Many of the Buddha’s disciples who became monks were brahmans and they brought with them the mnemonic skills they had been educated in. These same skills were used to preserve the Buddha’s suttas, his sermons, talks and sayings. Like the Vedas, the suttas are clearly designed to be chanted. They are full of mnemonic devices – rhyming verses, repetitions, numbered lists, stereotyped phrases, etc. Even before the Buddha’s passing, monks and nuns would regularly chant the suttas in congregation (D.III,207). This made it difficult to add, delete or change anything once a sutta had been settled and committed to the memory of the monastic community. It is also important to realize that lay men and women had a role to play in orally transmitting the suttas too. The Vinaya says that if a monk hears that a lay person who knows a sutta that he doesn’t is dying, the monk should go and learn it from them before they pass away. Inscriptions from Sanchi mention lay men and women who knew (i.e. by heart) suttas and sometimes whole collections of suttas. The Buddha said he wanted not just his ordained disciples but also his lay men and women disciples to be "knowers of the Dhamma" so that they could ‘pass on’ what they had learned to others (D.II,105). The oral transmission of the Tipitaka for two or even three hundred years was kids stuff compared to the 2500 years during which the Vedas were orally transmitted. It is interesting to know that long after writing came into vogue in India Buddhists continued to transmit the Tipitaka orally, believing, probably correctly, that it was more accurate than writing. When the Chinese pilgrim Fa-hsien was in Patna in the first decade of the 5th century he noted that although the Vinaya was written down the monks preferred to commit it to memory.
An amazing memory
Another indication of the authenticity of the Tipitaka is that there was a monk who memorized all of the Buddhist scriptures; all 20,000 pages and even the commentaries too!
Bhandanta Vicitsara recited 16,000 pages of Buddhist canonical texts in Rangoon, Burma in May 1954. After the Buddha's passing, parinibbana, there were 500 arahants reciting the scriptures and here recently we have a documented case of just one monk who could memorize the texts.