Alexander Lubotsky

"In order to account for this fact, we are bound to assume that the language of the original population of the towns of Central Asia, where Indo-Iranians must have arrived in the second millennium BCE, on the one hand, and the language spoken in the Punjab, the homeland of the Indo-Aryans, on the other, were intimately related."

"I use the term substratum to refer to any donor language, without implying sociological differences in its status, so that 'substratum' may refer to an adstratum or even superstratum."

"Another problem is how to account for Indo-Iranian isolates which have been borrowed into Uralic [...which form part of...] the new vocabulary, which most probably was acquired by the Indo-Iranians in Central Asia."

"In the case of Indo-Iranian, there may have been early differentiation between the Indo-Aryan and Iranian branches, especially if we assume that the Iranian loss of aspiration in voiced aspirated stops was a dialectal feature which Iranian shared with Balto-Slavic and Germanic (cf. Kortlandt 1978:115). Nevertheless, Proto-Indo-Iranian for a long time remained a dialectal unity, possibly even up to the moment when the Indo-Aryans crossed the Hindu Kush mountain range and lost contact with the Iranians."

"Starting with the assumption that loanwords reflect change in environment and way of life, we get the following picture of the new country of the Indo-Iranians. The landscape must have been quite similar to that of their original homeland, as there are no new terms for plants or landscape. The new animals like camel, donkey and tortoise show that the new land was situated more to the South […] This picture, which is drawn on exclusively linguistic arguments, is a strong confirmation of the traditional theory that the Indo-Iranians came from the north. […] as we have seen above, there are reasons to believe that the Indo-Aryans formed the vanguard of the Indo-Iranian movement and were the first to come into contact with the original inhabitants of the Central Asian towns. […] the Iranians […] were pushing from behind."