A Proto-Language is a hypothetical, reconstructed language that is believed to be the common ancestor of a group of related languages. Linguists use evidence from existing languages to infer the features and vocabulary of these ancient languages. For example, the Proto-Indo-European language is thought to be the ancestor of many modern languages, including English, Spanish, and Hindi. Studying proto-languages helps researchers understand how languages evolve over time. By examining similarities and differences among languages, they can trace back their origins and see how cultures and societies have interacted. This process reveals the rich tapestry of human communication and the connections between different peoples throughout history.