Step 1: Understanding the Concept:
The question asks about the specific languages used for Ashoka's edicts in the northwestern part of his empire, corresponding to modern-day Afghanistan.
Step 2: Detailed Explanation:
Emperor Ashoka's policy was to communicate his message of Dhamma in the language and script that were understood by the local population.
In most of India, his inscriptions were in Prakrit, written in the Brahmi script.
In the far northwestern parts of the Mauryan empire (modern Pakistan and Afghanistan), the population was diverse and included people of Greek and Persian descent due to centuries of interaction with the Achaemenid and Hellenistic worlds.
To reach this audience, Ashoka had his edicts inscribed in languages and scripts familiar to them. Consequently, inscriptions found in Afghanistan, such as the famous Kandahar Edict, are bilingual or monolingual in Aramaic (the administrative language of the former Achaemenid Persian Empire) and Greek.
Step 3: Final Answer:
In Afghanistan, the Ashokan inscriptions were written in Aramaic and Greek.