What evidence supports the view that Indo-Aryan speakers migrated into the Indian subcontinent?

The view that Indo-Aryan speakers migrated into the Indian subcontinent is supported primarily by linguistic evidence, though it remains a subject of scholarly discussion.1

Linguistic Evidence

Linguists argue that the migration theory is the most plausible explanation for the development of the Indo-Aryan languages. Specifically, the Vedic vowel system—which lacks short e and o—is difficult to reconcile with the theory that it is the direct ancestor of other Indo-European languages like Greek or Latin. It is methodologically simpler to conclude that these languages shared a common ancestor and that the Indo-Aryan branch migrated from an external homeland where these vowel sounds merged.1

Archaeological and Historical Context

While the "Aryan invasion" theory is now discredited, scholars generally accept that a series of migrations occurred beginning around the 2nd millennium BCE. Evidence from cemeteries at Sibri and near the Bolan Pass shows parallels in copper and bronze tools and pottery with sites in Tajikistan and Uzbekistan, suggesting contact with Central Asian groups.123

However, definitive archaeological proof of a mass migration is lacking, and some scholars maintain that Indo-Aryan culture was indigenous to the subcontinent.13