"Afghanistan v. Languages". Ch. M. Kieffer. Encyclopædia Iranica, online ed. Retrieved 10 December 2010. Persian (2) is the language most spoken in Afghanistan. The native tongue of twenty-five percent of the population ...
In 1990 the Russian language was declared as the official language of USSR and the constituent republics had rights to declare additional state languages within their jurisdictions. See Article 4 of the Law on Languages of Nations of USSR.Archived 2016-05-08 at the Wayback Machine(in Russian)
Shinji Ido. Bukharan Tajik. Muenchen: LINCOM EUROPA 2007
state.gov
See for example the Country report on Uzbekistan, released by the United States Bureau of Democracy, Human Rights, and Labor here.
uva.nl
dare.uva.nl
B. Rezvani: "Ethno-territorial conflict and coexistence in the Caucasus, Central Asia and
Fereydan. Appendix 4: Tajik population in Uzbekistan" ([1]). Dissertation. Faculty of Social and Behavioural Sciences, University of Amsterdam. 2013
In 1990 the Russian language was declared as the official language of USSR and the constituent republics had rights to declare additional state languages within their jurisdictions. See Article 4 of the Law on Languages of Nations of USSR.Archived 2016-05-08 at the Wayback Machine(in Russian)