The Vedas existed before Sanskrit was written down At first how had they been preserved?

Answer 1

Over time, Aryan Brahmins and scholars wrote their thoughts about the Vedas. These thoughts were complied into Vedic texts. These texts described rituals, explained how to perform sacrifices, and offered reflections from religious scholars.

The Vedas were transmitted orally from the first R^iShi(lit.Seer). It is to be noted that the R^iShi is not one who had composed the hymn. He was the first to "see" it. According to The Vedas, shabda(The Word) is Indestructible. From the Big Bang[Sphota] or the Primordial Sound, the frequencies and "sound quanta" that emerged are always present in Space(AkAsha). The R^iShi is merely Blessed with the special Auric power to get this sound in the right sequence and to just repeat it till its meaning becomes a Reality in the phenomenal world. Hence with every mantra or a set of mantras[Hymn as in R^ig Veda or Declarative/Imperative Statements as in the Yajurveda for instance ] a particular R^iShi is associated.

This revealed knowledge the R^iShi gave to the seekers without reserve. This was repeated by the disciples owing allegiance to the RiShi.

The trasmission of the same from generation to generation was always kept intact.

Not a letter is allowed to be shifted out of its place nor is the intonation allowed to be changed one wee bit. The only means of trasmittal from Guru to Shishya ensured this. Excellent and ingenuous methods of rendition were invented to ensure fidelity of transmission. these were called as the various kinds of pAThas[renditions] like pada-krama-Ghana-jaTA-shikhA and the like.

The kind of redundancy introduced due to these pAThas has what maintained the "accuracy" and faithfulness to the original till writing was invented to get the same into book form.