When was Proto-Indo-European probably spoken?

Proto-Indo-European (PIE) is widely believed to have been spoken approximately 6,000 years ago. While determining a precise date through linguistic evidence alone is difficult, most scholars agree that the language must have begun splitting into distinct branches before 3000 BCE, though the initial divergence likely did not occur much earlier than 4500 BCE.123

Some researchers propose alternative timelines depending on the hypothesized location of the Indo-European homeland. For instance, the Anatolian hypothesis suggests an earlier origin in the 7th millennium BCE. However, the most prominent theory associates PIE with the Pontic-Caspian steppe region, where significant expansion and fragmentation of the population occurred around 4000 BCE. Because PIE speakers did not have a writing system, these dates are reconstructed through linguistic analysis and correlation with archaeological evidence.231