Short answers, pulled from the story.
The Behistun Inscription was carved in the 6th century BCE and represents Old Persian, the first known appearance of the language. This inscription was ordered by King Darius I and remains unreadable to most of the world for over two thousand years.
Middle Persian transitioned to New Persian over several centuries, with the language fully emerging as a literary force by the 9th century. This evolution began in the capital city of Ctesiphon, where the Dari dialect from northeastern Khorasan flourished and eventually became the foundation for modern Persian.
Persian served as the sole official language of the Indian subcontinent for five centuries prior to British colonization under the Mughal emperors. The language was introduced to the region by Turkic Central Asian dynasties and shaped the development of modern languages such as Urdu, Hindi, and Bengali.
The Academy of Iran was established in 1935 under Reza Shah Pahlavi to lead massive campaigns replacing foreign loanwords with native Persian terms. First official attempts to protect the language from foreign words were made in 1871 under the Qajar dynasty when the Tehran dialect rose to prominence.
The Persian language has approximately 130 million speakers worldwide and exists in three standard varieties: Iranian Persian, Dari, and Tajik. Iranian Persian and Dari use the Perso-Arabic script while Tajik uses the Cyrillic script, yet all three varieties remain mutually intelligible.