The name for the collection of teachings is the Tipitaka or Pali Tipitaka, also see Pali Canon
There are different types of writing within Buddhism, they are generally divided into three parts, the teachings of the Buddha as passed down and recorded in the Buddhist tradition, commentaries and explanations on the teachings of the Buddha and finally all other texts.
Writing was present in India for 1500 years before the birth of the Buddha. Writing down his words was no real problem.
The teachings of the Buddha were first passed down orally by his disciples after his death around 483 BCE. These teachings were later compiled into written texts in the first century BCE.
The Tipitaka contains different histories and teachings of Buddha. The contents of the Tipitaka were handed down orally and then finally put into writing. It is not clear as to who the contributors were.
The complete teachings of the Buddha were first written down in Sri Lanka, at Alu Vihare.
The Buddha's teaching were first preserved orally by his followers and then later were written down.
There are no required books. It's possible to be illiterate and still practice Buddhism well. On the other hand, although the Buddha himself (like Jesus) never wrote any books, his teachings were passed down orally for centuries and eventually written down. If you are interested in reading some, here are two excellent anthologies: BASIC TEACHINGS OF THE BUDDHA, Glenn Wallis, ed., (Modern Library) and IN THE BUDDHA'S WORDS, Bhikkhu Bodhi, ed. (Wisdom). .
His followers and disciples wrote down his oral (spoken) sermons, lessons and teachings after his death. His teachings were also transmitted orally from teacher to student, in the various lineages of Buddhism.
It is for reverence for what the Buddha brought to us (the Dharma (teachings)). But in general a Buddhist will bow to most people as a greeting. It is done to show humility and resepct to the person being greeted.
The Tripitaka (three baskets) is a set of books that contains the Buddha's teachings. It is comprised of the Sutras, sermons and teachings of Buddha; Abhidharma, discourses on interpretation of the doctrine; and Vinay, rules for monks and nuns in monastic life. So the Tripitaka defines what Buddhism is and how we are to live our lives.
In the Mahayana tradition a follower seeks to attain enlightenment not only for themselves but for the benefit of all sentient beings. These people are referred to as Bodhisattvas. The Mahayana tradition is the largest of the two Buddhist traditions active today. It was started sometime about 400 years after the Buddha's death. One of the great Masters of Mahayana was Nargajuna who taught on emptiness.The Theravada tradition was started after the Third Council after The Buddha's death. This council was held to remove some heretical beliefs and writings from the scriptures that were seeping into the teachings. The Buddha's teachings were written down and approved by this council and is known as the "Teachings of the Elders". The main goal of a Theravadan is to attain Buddha-hood. It is the oldest school and the one most closest to the early Buddhism.The Theravada tradition was started after the Third Council after The Buddha's death. This council was held to remove some heretical beliefs and writings from the scriptures that were seeping into the teachings. The Buddha's teachings were written down and approved by this council and is known as the "Teachings of the Elders". The main goal of a Theravadan is to attain Buddha-hood. It is the oldest school and the one most closest to the early Buddhism.Read more: What_is_the_difference_between_two_main_branches_in_Buddhism
The first language was in Pali . this is only cause Buddha is said to live in the Pali kingdom and they wrote it down. most Buddhist at that time could not read or right. Also the teachings were past down by Buddha and bodhisattvas in speech. I'm sure some books were also written in Sanskrit later on.