dentals in Indo-Aryan; morphologically there are the gerunds; and syntactically there is the use of a quotative marker (iti). These are taken as evidence of substratum influence. It has been argued that Dravidian influenced Indic through "shift", whereby native Dravidian speakers learned and adopted Indic languages. The presence of Dravidian structural features in Old Indo-Aryan is thus plausibly explained, that the majority of early Old Indo-Aryan speakers had a Dravidian mother tongue which they gradually abandoned. Even though the innovative traits in Indic could be explained by multiple internal explanations, early Dravidian influence is the only explanation that can account for all of the innovations at once – it becomes a question of explanatory parsimony; moreover, early Dravidian influence accounts for several of the innovative traits in Indic better than any internal explanation that has been proposed. A pre-Indo-European linguistic substratum in the Indian subcontinent would be a good reason to exclude India as a potential Indo-European homeland. However, several linguists, all of whom accept the external origin of the Aryan languages on other grounds, are still open to considering the evidence as internal developments rather than the result of substrate influences, or as adstratum effects. Archaeology: migrations from the steppe Urheimat The Sintashta, Andronovo, Bactria-Margiana and Yaz cultures have been associated with Indo-Iranian migrations in Central Asia. The Gandhara Grave, Cemetery H, Copper Hoard and Painted Grey Ware cultures are candidates for subsequent cultures within south India associated with Indo-Aryan movements. The decline of the Indus Valley Civilisation predates the Indo-Aryan migrations, but archeological data show a cultural continuity in the archeological record. Together with the presence of Dravidian loanwords in the Rigveda, this argues in favor of an interaction between post-Harappan and Indo-Aryan cultures. Stages of migrations About 6,000 years ago the Indo-Europeans started to spread out from their proto-Indo-European homeland in Central Eurasia, between the southern Ural Mountains, the North Caucasus, and the Black Sea. About 4,000 years ago Indo-European speaking peoples started to migrate out of the Eurasian steppes. Diffusion from the "Urheimat" Scholars regard the middle Volga, which was the location of the Samara culture (late 6th and early 5th millennium BCE), and the Yamna culture, to be the "Urheimat" of the Indo-Europeans, as described by the Kurgan hypothesis. From this "Urheimat", Indo-European languages spread throughout the Eurasian steppes between c. 4,500 and 2,500 BCE, forming the Yamna culture. Sequence of migrations David Anthony gives