Proto-Indo-European is thought to be the ancestor language of English, Latin, Greek, French, Russian, Urdu, Sanskrit, Farsi, and dozens of others. But what did it sound like?
Historical linguistics is able to trace the evolution of languages. It’s a difficult process, starting with the languages still extant today and working backwards. Commonalities between languages can tell you that they may have a shared origin. We know something of how sounds in a language change over time, often according to specific rules. Together, this evidence can give you a decent – albeit entirely hypothetical – idea of what extinct ancestor languages may have sounded like.
The English language has picked up words and grammar from any number of languages, but its core and origin is Germanic; the same is true of Dutch, Swedish, modern German, and others. French, Spanish, and Italian evolved from Latin. Welsh, Irish, and Gaelic have a common ancestor, as do Polish, Albanian, Russian, Lithuanian, Serbian, and more. Farsi, Pashto, Kurdish and many others can likewise be grouped together. In India and Pakistan, Urdu, Hindi, Punjabi, and Gujarati share the common ancestor language Vedic Sanskrit. But here’s the thing: if you go back far enough, all of the languages listed here are related. Go back far enough, and they all have a common ancestor.
Proto-Indo-European is a hypothetical language that serves as the ancestor for hundreds of languages stretching across Europe, the Middle East, and Asia. Like a tree of many branches, it has spread across two continents in the last few thousand years. It would have been actually spoken between 6500 and 4500 years ago.
(Side note: this does not necessarily mean that the people speaking all these languages are genetically related. History is full of language shifts, conquerors imposing their language on others for example, so be cautious conflating language ancestry and biological ancestry.)
But what did it sound like? We’ll never know for sure, but using those commonalities and rules of change I mentioned above we can reconstruct a best-guess at what it sounds like. The recording in the last link below is from linguist Andrew Byrd, reciting a piece of dialogue called “The king and the god.”
“The King and the god” is adapted from a Sanskrit hymn; Vedic Sanskrit is an important source for our understanding of Proto-Indo-European because its sounds have been so well preserved (thanks to memory culture).