Why did Mishnaic Hebrew gain literary importance in the 2nd century BC?

Mishnaic Hebrew gained literary importance in the 2nd century BC primarily because the Pharisees began to employ the dialect in their teachings.1

As a distinct dialect that developed during the period of the Second Temple, Mishnaic Hebrew served as a vital tool for religious and legal discourse, eventually becoming the language of the Mishna—a foundational collection of Jewish traditions and laws. While Biblical Hebrew had largely ceased to be a spoken language by this time, Mishnaic Hebrew provided a precise and pedestrian idiom that allowed scholars to document oral traditions and consolidate legal material. This shift marked a significant evolution in Hebrew literature, enabling the language to adapt to the needs of changing religious and intellectual life.1234