<P> The Russian Empire in Russian Turkestan implemented Turkification upon the Ferghana and Sarmakand Tajiks replacing the Tajik language with Uzbek resulting in an Uzbek dominant speaking Samarkand whereas decades before Tajik was the dominant language in Samarkand . </P> <P> The creation of the Tajik Soviet Socialist Republic within the Soviet Union in 1929 helped to safeguard the future of Tajik, as it became an official language of the republic alongside Russian . Still, substantial numbers of Tajik - speakers remained outside the borders of the republic, mostly in the neighboring Uzbek Soviet Socialist Republic, which created a source of tension between Tajiks and Uzbeks . Neither Samarqand nor Bukhoro was included in the nascent Tajik S.S.R., despite their immense historical importance in Tajik history . After the creation of the Tajik S.S.R., a large number of ethnic Tajiks from the Uzbek S.S.R. migrated there, particularly to the region of the capital, Dushanbe, exercising a substantial influence in the republic's political, cultural and economic life . The influence of this influx of ethnic Tajik immigrants from the Uzbek S.S.R. is most prominently manifested in the fact that literary Tajik is based on their northwestern dialects of the language, rather than the central dialects that are spoken by the natives in the Dushanbe region and adjacent areas . </P> <P> After the fall of the Soviet Union and Tajikistan's independence in 1991, the government of Tajikistan has made substantial efforts to promote the use of Tajik in all spheres of public and private life . Tajik is gaining ground among the once - Russified upper classes, and continues its role as the vernacular of the majority of the country's population . There has been a rise in the number of Tajik publications . Increasing contact with media from Iran and Afghanistan, after decades of isolation under the Soviets, is also having an effect on the development of the language . </P>

To which of the following languages is tajik most closely related