How did Aramaic spread across the Middle East under the Achaemenian Empire?

Aramaic, a Semitic language, became the primary administrative language of the Achaemenian Empire, serving as the lingua franca across the Middle East.123

Its widespread use was established prior to the Achaemenid period. By the 8th century BCE, the Assyrians had adopted Aramaic as a second language, and subsequent mass deportations by the Assyrians, combined with its use by Babylonian merchants, facilitated its expansion. By the 7th and 6th centuries BCE, it had successfully supplanted Akkadian as the dominant lingua franca of the region.2

When the Achaemenian dynasty rose to power, they adopted Aramaic as the official language of their imperial bureaucracy. While the empire utilized various languages—such as Old Persian, Elamite, and Akkadian for royal inscriptions—Aramaic was the most widely used medium for administrative communication. Its influence was so profound that it began to impact the Persian language itself, a trend clearly visible in royal inscriptions from the late Achaemenid period.123