Which people of the indus river valley left a significant amount of literature yet no architectural artifacts, making it difficult to determine their origins?

The people of the Indus River Valley who left a significant amount of literature yet no architectural artifacts, were the Aryan people. That made it difficult to determine their origins were.

"Aryan" was a term used as self-designation by Indo-Iranian people. The term was used by the Indic people of the Vedic period in India as an ethnic label for themselves and to refer to the noble class.