"There was a branch of Indo-Aryan which, like the parent Indo-European, had retained the distinction between r and l, [and that this branch entered India] before the migrations of the standard Indo-Aryan branch... Where did they come from? Did they reach India via Iran? If so, did they leave any trace of themselves in Iran? Were the speakers of the r-and-l dialect of pre-Vedic Indo-Aryan a totally different branch from the Indo- Iranian? These are difficult questions. [...] Anyway, one would still have to assume the entry of r-and-l dialects of Indo-Aryan into India before the arrival of the Ṛgvedic Aryans to account for the fact that r-and-l dialects in India were more easterly in relation to the Ṛgvedic dialect."