This is the day when all Pashtuns are encouraged to speak/write Pashto every chance they get, keeping it as pure as possible.
Pashto (alternatively spelled Pukhto, Pakhto or Pushto), also known historically as Afghani and Pathani, is the native language of the Pashtun people of South-Central Asia. Pashto is a member of the Eastern Iranian languages group. The word "Pashto" derives by regular phonological processes from Parsawa- "Persian".
Pashto is one of the two official languages of Afghanistan (the other being Dari (Farsi)), and is also spoken as a regional language in western and northwestern Pakistan and among the Pashtun diaspora around the world.
Pashto belongs to the Northeastern Iranian branch of the Indo-Iranian language family, although Ethnologue lists it as Southeastern Iranian. The number of Pashtuns or Pashto-speakers is estimated to be 40–60 million people worldwide.