Quote Originally Posted by Hanna View Post
I am just curious - how do you Ukrainians know what language to use in different social situations?
With a stranger at the bus stop... in the market.... at university.. in a shop or department store...?
Regardless of where an informal conversation with a stranger happens (between locals) the language is generally depends on the language used in this region, and most regions are pretty homogeneous in this regard (with slight deviation between cities and country areas). In other words there's no social rule that in a department shop you should speak one language, and at a beauty salon another - it's usually one language all the way.

In areas where both languages are widespread (like Kiev) strangers on the street can swap to one language or the other, but quite often they speak both - i.e. each one uses his/her own language of preference. It does not cause any difficulties in understanding, since an absolute majority of Ukrainians are bilingual (at least at comprehension level).

In official or semi-official situations, especially if the target audience is all-Ukrainian (political speeches or announcements, for example), Ukrainian is used almost exclusively, since it's required by law. It's also required of most state office clerks, who communicate with public. But if the said event is local (in a Russian speaking region) most people use Russian since there's no one to tell them otherwise.
Do you always speak the same language with some people, or do you vary even with your friends?
What happens if a particular friend is better at one of the languages while the other prefers the other language?
It's an interesting question, I think it's possible to talk with different groups of friends in different languages, but said friends should probably have drastically different backgrounds...
Personally I do not have anyone to speak to in Ukrainian here. I grew up in a very homogeneous region (I was 11 when I've fleetingly seen a genuine Ukrainian-speaking person for the first time in real life (not on TV)). later I moved to another region, but it's also mostly Russian speaking, or rather cities are almost exclusively Russian-speaking and villagers and people from small towns speak "surgik" (a mix of both languages).
But I had a friend at Uni, who spoke Russian (as everyone else), and only after her Dad visited, I realized that they spoke "surgik" only at home, because she switched between two seamlessly. It was cool (even if "surgik" is often considered a "hillbilly" dialect). In other words, most people adapt to general language setting, if they move somewhere with different language preferences, so there's no Babel confusion.