Indo-Iranian languages, group of languages constituting the easternmost major branch of the Indo-European family of languages; only the Tocharian languages are found farther east.
The above scenario assumes that the Indo-Aryans migrated into the Indian subcontinent. There are scholars, both Indian and non-Indian, who maintain that the Indo-Aryans originated in the subcontinent, whence they emigrated.
Also awaiting further research is the identification of the Harappan peoples of the Indus Valley and other sites in the subcontinent, whose writing has not yet been satisfactorily deciphered despite decades of effort.
A definitive solution to this problem could possibly answer the question of whether Indo-Aryans encountered these people or whether Harappan civilization had passed by the time the Indo-Aryans arrived on the subcontinent, although scholars now generally agree that the Indus Valley civilization’s decline was not due to any Indo-Aryan invasion.
Moreover, the textual evidence from Sanskrit sources that some have claimed demonstrates that Indo-Aryans retained memories of an earlier homeland from which they migrated into the Indian subcontinent is small and subject to serious doubt, as it serves to support this thesis only with considerable interpretational effort.
The linguistic evidence, on the other hand, is best reconciled with the thesis that the Indo-Aryans did indeed go to the subcontinent from an external homeland and that the early Vedic system is not equivalent to that of Proto-Indo-European.