Proto-Indo-European (PIE) ~4000–2500 BCEThe root of Sanskrit, Greek, Latin, and other Indo-European languages.Developed in the Pontic-Caspian Steppe (modern Ukraine/Russia), though some argue for an Indian or Armenian homeland.Proto-Semitic (PS) and Proto-Indo-European (PIE) are entirely different language families with different structures, phonetics, and grammatical systems.Image shows how the word 'two' evolved from PIE: