Vedic Sanskrit has linguistic similarities with other Indo-European languages
We may infer that the Vedic people were agriculturists or pastoralists from their hymns
Understanding Hinduism notes that South Indian priests instructed North Indian priests in Vedic ritual after Islamic suppression of Hinduism. This is evidence of the cultural affinity between North and South (see Breaking India to see how various forces are alienating the South from the North).
I like Understanding Hinduism even better than Klaus K. Klostermaier's book A Short Introduction to Hinduism. Understanding Hinduism is the best introduction to Hinduism that I've read: therefore, I'm rating it 5 stars.