Guys, this discussion - as it is now - seems to be pointless.
Everyone is a linguist here and knows perfectly well how a language works.
First of all,
Ukrainian IS a unified language because it is has the Standard with fixed rules which is spoken by people (that have received higher education and live in towns/cities) in ALL parts of Ukraine. Of course, there are
regional dialects - as in any other language, and of course, they may be used in informal situations by those who otherwise speak Standard, but they
don't prevent the mutual understanding among Ukrainians (mind, Ukrainians because I'm not sure about the understanding of Russian speakers who have learned Standard Ukrainian). However, some dialects of the South-Western group are very much distinct form the Standard and one may have lexical difficulties in comprehending them (I'm speaking of Boiko, Lemko and Hutsul dialects and the
Rusyn language which is a controversial point - Ukrainians consider it to be a dialect, Rusyns - a separate lanugage).
And in the posts above I've noticed some inaccuracies:
Hutsul dialect is not a base for Standard Ukrainian! And
it HAS NOT "appeared suddenly in the years immediately following WWII"! It has always been there since the begging of its formation in Kyiv Rus' in the 11-12th c. The year 1789 is considered to be the start of
Standard Modern Ukrainian, formed on the basis of Central dialects (Наддніпрянський, mainly, though here I'm not totally sure, I'll have to check it).
Naturally, in the course of history Ukrainian has experiences and sometimes suffered influences of Russian, Hungarian, German, Polish (and now English) but that's a different topic for discussion.
P.S. I believe I'm exposed to західнополіський, волиський and наддністрянський dialects but I'm perfectly aware what may be dialectal in my speech and can either use it or not. I'm sure, most of the speakers of so much frightening Western dialects can do so too, so the situation is not like Victoria (#14) has described: if you go there and know only Standard name for rooster (півень), everyone will understand you
