I don't think that anyone was prosecuted strictly because of speaking/teaching language. But there were Kazakh intelligence (who probably promoted language among other national agendas) prosecuted for opposing soviet regime. Again, I don't think that language itself has anything with it. That said, yes, USSR forced other nations to adapt Russian language and it's understandable that those nations didn't like it. But it was almost a century ago, we are living in current conditions, so it's wiser to remember the past, but plan the future according to current realities, not some 100-year old dreams.