Also known as Persian, Farsi is spoken by an estimated 110 million speakers mostly in Iran, Tajikistan, Uzbekistan, Iraq, Russia, Azerbaijan and Afghanistan. In some of these countries, the language has other official names such as Dari in Afghanistan and Tajik in Tajikistan.
Farsi today is an extension of Middle Persian, which is in turn a continuation of Old Persian. Middle Persian was spoken during the time of the Sasanian Empire while Old Persian was spoken during the period of the Achaemenid Empire.
Persian is a language that has its roots going all the way back to c. 3000 BCE. As it is an Iranian language, it also falls into the three periods that Iranian languages fall into, that is, Old, Middle, and the Modern period. Interestingly, documents show that Farsi is the only Iranian language with strong philological ties with all three periods. These strong ties mean that all varieties of Persian spoken in the three eras all point back to the one spoken in the old period.
New or Modern Persian, which is spoken today, has three further subdivisions namely Early New Persian, Classical, and Contemporary Persian. Early New Persian’s period was either the eighth or the ninth century. Regardless, New Persian has been largely unchanged since then.
In total, the language has three varieties namely the aforementioned Dari and Tajik as well as Western Persian. Western Persian has many speakers in Iran as well as a small number of speakers in the Persian Gulf states and Iraq. All the three varieties also have local dialects such as the Hazaragi dialect in Pakistan and Afghanistan, Herati in Afghanistan, and Tehrani in Iran. For the three countries where Farsi is the official language, language experts have established that there is a high level of mutual intelligibility. A high level of mutual intelligibility means that speakers of these languages can understand one another easily.
In addition to the three varieties, there are other languages that have a close resemblance to Persian and can be classified as dialects. These languages include Luri (which is spoken in the southwest of Iran in places like Fars Province and Lorestan) and Tat (spoken in Russia, Azerbaijan, and Transcaucasia). The language has also had considerable influence on other languages like the Turkic languages as well as Armenian, Indo-Aryan, and Georgian languages.
Another language that Farsi has influenced is Arabic, especially Arabic in Oman and Eastern Arabia. Persian also adopted much vocabulary from Arabic after the 651 end of the Sasanian Empire of Persia. Persian also helped to break the monopoly that Arabic had during that time, especially in writing. Famous works done in Persian include the Rubaiyat of Omar Khayyam and the Shahnameh of Ferdowsi.