You forgot to mention that Crimea Tatars, Greeks, and Ukrainians were deported and murdered in Crimea. It's easy to make Crimea speak any language this way.
However, in times before mass-education was started and official variant of Russian language was developed, the folk variant of language spoken there was called "molva", which now known as Ukrainian language ("mova").
Well, yes - this deportation happened and is one of the many dark moments in USSR history. Glad you brought this up - difficult to write the entire history of the region on hn. The history of the Pontic Greeks and then later, Italian city states, in the Black Sea is really fascinating.
Molva (~rumors, «народная молва») was common name of folk language spoken at territory of (Kievan) Russia. Later it was replaced by official developed language, called yazyk ( tongue, «язык»), which was based on ancient dialect of South Slavic language, as spoken in Russian churches.
However, leaders of folk movement, later known as Ukrainians, developed and enhanced folk language, which then was renamed into Ukrainian language, and used as one of symbols of independence from Moscow, so it was systematically suppressed by government of Russian Empire, Soviet Union, and Russian Federation.
Crimean Tatars constituted the majority of the population of Crimea before the Russian conquest. They became the minority partly through genocide, and partly because the peninsula was settled by Russian colonists.
Ukrainians, on the other hand, were never indigenous in Crimea. It was not a part of Kievan Rus, so any Ukrainians who lived there, immigrated there after the Russian occupation of it. And there are so few mostly because most immigration to it was orchestrated, and the Imperial government preferred to settle it with Russian rather than Ukrainian colonists.
So in one case, you can talk about genocide of the indigenous population. In the other case, it's preferential treatment of one ethnicity over another for colonization purposes.
