Do you wonder why you, an ordinary (but special!) human, know hundreds, maybe thousands of songs? Why you can sing along to songs that were on the radio many years ago? Why do tiny kids love songs and want to sing? It is our birthright. Before we could write, and maybe before we could talk, humans could sing. That was how humans preserved their cultural history - with song.
There still exist very ancient stories and poems, that at one time were unwritten and passed along singer to singer. The Vedas is an example.
The oral tradition of the Vedas (Śruti) consists of several pathas,
"recitations" or ways of chanting the Vedic mantras. Such traditions
of Vedic chant are often considered the oldest unbroken oral tradition
in existence, the fixation of the Vedic texts (samhitas) as preserved
dating to roughly the time of Homer (early Iron Age).
It is not hard to imagine a world without Youtube where people got together and sang the songs that marked their cultural identity. That was our world. Sometimes it still is our world. You can hear it when that song comes on and everyone starts to sing.