According to proponents of the Aryan invasion theory the only thing that really marks the Aryans is their language. No other specific cultural trait or artefact can be clearly related to them. Yet even here we have a paradox. Sanskrit is supposed to be the language of primitive invaders and yet it is, by the opinion of many, one of if not the most refined language in the world. It has been regarded as the best language for computers because of its clarity. It is also a highly self-contained language developing organically out of specific roots, quite unlike English which is a mixture of various different languages like old German, Danish and French, with an admixture of Greek and Latin, reflecting a land that was invaded by many different peoples.

Moreover Sanskrit is a highly musical and metrical language. It possesses the oldest and most sophisticated grammatical science, going back to a period before the Buddha to the time of Panini and before, as he mentions several older grammatical traditions, some of which can be found in Vedic texts. Even the oldest Sanskrit, that of the Rig Veda, is done in complex meters and filled with various sophisticated plays on the sounds of words. It is a language filled with synonyms indicating a long and rich development. Above all it has an entire mysticism of sound, mantra and the Divine Word.

In other words Sanskrit does not appear as the legacy of barbarian hordes but that of an old, venerable, sophisticated poetic culture. Such a language requires a culture to produce it. This refined language fits quite well with the refined culture of Harappa but not with that of the Aryan invasion.