"Less clear is whether all Indo-European languages derive from this group, or whether just a subset do, says Paul Heggarty, a linguist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. He suspects that the Yamnaya spoke a language that later developed into Slavic, Germanic and other northern European tongues, but he doubts that they imported the predecessor of southern European languages such as ancient Greek, or those of eastern Indo-European languages such as Sanskrit."