This paper is based mainly on the results of the post-war Soviet censuses concerning respondents' native language and second language. The statistical data on Yiddish were studied for the former union republics of the USSR and their capitals. For Belorussia, Ukraine and the Russian Federation, the data were also studied for their different regions. In the 1994 Russian microcensus, a question on the primary language of conversation at home was asked for the first time, and the respective data concerning Yiddish in the city of Moscow and Birobidzhan ("Jewish") oblast were analyzed.
This paper was presented at the conference "Yiddish in the Contemporary World" at Oxford, 19-21 April 1998, and revised in May 2012.