Did you ever play the game of telephone as a kid? I know when my friends and I played it, we would purposely distort the message to make the outcome funnier.
Sometimes people think that’s how the Bible’s oral history happened. Bill Nye the Science Guy made this exact analogy, in fact. Such folks argue that nobody has a clue what the original message was because it got so distorted in transmission.
But that analogy is flawed. Deeply. It shows an ignorance about oral culture. When you have no paper or iPhones, you remember stuff better as part of everyday life. Because you depend on memory. And you're trying to remember precisely.
Consider just one of the ethnology texts from Genesis. (An ethnology is like a genealogy except that it sometimes leaves out generations in which pretty much nothing happened). Imagine passing this down the telephone line:
Today’s translators go all the way back to the oldest transmissions rather than using the message from the closest person on the wire. In the bird-on-the-wire analogy, they skip the last 20 birds and get as close to “Mama’s message” as possible.