Here's why:
* Alexander the Great's conquests: Alexander's campaigns spread Greek culture and language across a vast area.
* Common language: Koine Greek, a simplified version of the Classical Greek dialects, emerged as a common language for trade, administration, and intellectual discourse across the Hellenistic world.
* Literary and philosophical influence: Major writers like Epicurus, Zeno of Citium, and Euclid wrote in Koine Greek.
* Cultural exchange: Koine Greek facilitated the transmission of knowledge and ideas, leading to a flowering of Hellenistic culture.
While other languages continued to exist within the Hellenistic world, Koine Greek served as the lingua franca, bridging cultural and linguistic divides.