Tajiki is the dialect of Persian spoken in Tajikistan, and in the various nearby regions Uzbekistan, Kazakstan, Kyrgyzstan, Russia, Turkmenistan, Ukraine and Afghanistan. It is the language of the great old Persian cities Samarqand, Bokhara and Balkh. It has been written with Cyrillic letters since 1940.
Chart
Here is the transliteration of Farsi/Dari letters into the Cyrillic of Tajiki:

