Next to English, what is the lingua franca of Eastern Europe? Russian? German? French? Some other language?
There is none.
Older people in areas of former Austria-Hungary might speak German with each other, but younger people - even those who speak German - will rather speak English to each other.
Areas to the east, it's Russian.
I'd say it's something like this in Lithuania:
40 year olds and above - great russian / poor-average english
30-40 - good russian / decent english
Below 30 - Good-great english / poor russian (unless has some russian, ukrainian, belarussian, etc in the family)
And you can find some German speaking people in Klaipeda.
>Finnic languages not eastern european
>Finnic languages not lingua franca
nice one US
>living in the past
sub-regions according to EuroVoc