Translation of sentences from other-language corpuses

I guess there is no problem especially if you translate from languages of the same family so that the translation is good. In general at Common Voice “original” sentences are preferred because the point is to find sentences that are more natural possibly, but I guess if you translate from Ukrainian or Belarusian it should work. But also I suggest: why not writing sentences on your own? I think the work of translating a sentence or inventing a new one is roughly the same or, even better, try to find some CC-0 source in Russian.