Audio information is ubiquitous, but does not form part of the permanent record in the way the printed record does. To the extent that there are 'recordings' and more recently digitalization of audio information, these data can become a more permanent part of the record.
Some of the history of the audio record in intersting. The origin of the word 'audit' goes back to the way people gave an account when people engaged in commerce understood the transaction did not know how to read and write. According they were told about the accounts.
In my own career experience, I did some work for a very wealthy Nigerian who did multi-million dollar commercial transactions without being able to read or write. Most of the time, his commercial instincts worked for him, but not always. My company became involved because he had misunderstood exactly how a shipload of rice was going to be packaged. In fact it was bulk rice rather than bagged rice, and his organization had no way of handling the rice in this form. This is where we came in. But the idea that he had purchased this amount of product without being able to read or write, gave me cause for thought.
People to people ... rather person to person, audio communication is of critical importance in a society where quality of life is optimized. This has been diminished over time, and it is a bad trend. Human beings are social, and audio information, audio communications is valuable.