The civilization of Indus River Valley is considered one of the three earliest civilizations in world history, along with Mesopotamia and Egypt. Bigger geographically than those two as it unfolded starting in 3300 BCE across what is now Pakistan and India, the Indus civilization boasted uniform weights and measures, skilled artisans, a multifaceted system of trade and commerce, and upwards of 500 symbols and signs for communicating.But one question has vexed scholars for decades and hindered attempts to learn more about this civilization: Were those characters a language or more akin to pictograms? Even as some experts begin to translate...