JMA---you bring up an interesting point---the SU after 1945 and under Stalin took a move to ensure in the new eastern bloc that Russian was the primary language thus they started "forced" immigration of ethnic Russians into areas that were not previously Russian ethnic areas--remember the SU at the height of the Cold War had over 136 primary different languages and as was English/French were the official languages in Africa during the colonial period so was Russian the official language. This was also true in say Poland, Hungary, the former Czechoslovakia.
In the Ukraine virtually all Ukrainians speak Russian.
In the "stans" one will find pockets of ethnic Russians as well.
IMO the Putin Doctrine is dangerous as he can on a wim change the definition---meaning today it is language/ethnicity/culture and tomorrow what raw resources Russia needs to survive on, or a perceived "threat".
IE a demonstrator is killed in the Donetsk and the Russian FM states we will move in to defend Russians if the Ukrainians cannot control their country.
They claimed he was Russian when in fact the was a proUkrainian member of a right wing party.
Now with the latest claim of capturing of a US drone over the Crimea (one could argue they were attacked by NATO)---a Hunter ---which they claimed was launched from Bavaria by the 66th MI Group which is actually stationed in Darmstadt.
****By the way the Hunter has only a range of 125 miles which if my geography is correct it could have never reached the Crimea much less loiter over it. Unless it was launched by the Navy.
The wim can be redefined to whenever he wants it to mean--that is the dangerous aspect of the Doctrine and it stands on its head the Westphalia Treaty in the 1700s and the respecting of territorial borders since the end of WW2.
This has nothing to do with "spheres of influence" ---it is all about annexation and rebuilding of the former SU pure and simple. Remember Putin served as a KGB officer in Dresden in the GDR during his cold war days. He never did like the breakup of the SU and was vocal about that in a number of recent interviews.
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