After the WWII and Soviet oppression, the Jewish population in Lithuania was reduced from 250,000 to 5,000. Now that population is seeking to revive Yiddish, the language which was commonly used amongst Lithuanian Jews in an era when Lithuania was a Jewish center in Europe (for more on another Jewish center in Europe, check out the History of Josefov in Prague). Because the parents of some children today never learned Yiddish, it is their children who will see it stays alive for future generations.
The official language, Lithuanian, went through a revival as well, after Lithuanian language books were banned, Lithuanians fought to maintain the right to read and write in their own langauge.