The Tajik language belongs to the sub-group of Persian languages of the south western Iranian group of the Indo-European family of languages. The language had formed on the basis of Farsi and some of the eastern Iranian languages spoken in the 9th-10th centuries on the territory of Transoxiana and Khorasan.

* After the Persian territories had become part of the Arab Caliphate, Farsi developed under the influence of the Arabic. This influence continued through several centuries. This accounts for the presence of Arabic words in Farsi vocabulary and, later on, in the Tajik language. However, Arabic was not the only language that influenced Farsi. In AD 962 the Turkic Ghaznavid dynasty was established in Afghanistan. In 985 the Seljuk Turks moved to the vicinity of Bukhara and later in 999 the Ghaznavids defeated the Samanids in Khorasan, and the Qarakhanids captured Bukhara, the Samanid capital. The military conflicts between various Turkic tribes continued until the 13th century – Genghis Khan’s invasion of Central Asia. Whilst, during this period of turmoil, Farsi remained the official language of state, it adopted numerous words from the Turkic invaders.

* The second half of the 19th century witnessed the merger of the literary language with the speech of the Tajik dialect, yet these modifications did not make any considerable impact on the established literary norms. In the 20th century, the language of the Persian-speaking population of Central Asia acquired a new name – the Tajik language. This term is closely related to the political events that took place in Central Asian region in the first decade of the 20th century.

* In 1924, following the national-territorial division of the USSR, the Tajik Autonomous Soviet Socialist Republic was formed. The Tajik literary language developed on the basis of the living Tajik speech on the one hand, and on the classical Persian- Tajik literature on the other.