Even though it used to be spoken throughout most of Europe and Asia, the Proto-Indo-European (PIE) language is no longer spoken by anyone. That is partly because it was in use mainly between 4,500 and 2,500 B.C., and also because in the modern era we simply haven't known how to pronounce ancient languages correctly. But thanks to decades of research, there is now an audio example of how the language might have sounded.
Andrew Byrd, from the Linguistics Department at the University of Kentucky, recorded himself reading a parable written in PIE and published it to SoundCloud. We gotta say, it sounds at once weird and a tiny bit familiar. And it should sound familiar — it is the common language that birthed English, Farsi, and many other world languages. The speech was taken from a written example that German linguist August Schleicher created in 1868 as an experiment with writing in PIE. The text tells a parable of sheep and horses, appropriate material for 4,500-plus years ago.
Of course, Byrd's pronunciation is by no means unequivocally correct, and he himself described it as "a very educated approximation." He also pointed out that if you wanted to find out how that language was actually spoken, you would need a time machine. But honestly, if we went back in time, someone might accidentally keep English from being developed, which would be really inconvenient.