A lot of linguists believe that Proto-Indo-European was the ursprache* of Indo-European languages, but we actually don’t know what Proto-Indo-European sounded like. In the link below, a linguist at the University of Kentucky, Dr. Andrew Byrd, gives his best approximation of what our ancestors may have spoken thousands of years ago. When I listened to it, I was amazed that someone could recreate the language! Let me know what you think!
*I wrote about the word ursprache here: https://thewordexplorer.wordpress.com/?s=Ursprache