As with a lot of family names originating in Eastern Europe the "translation" into English generates variations in spelling, a fact sometimes exacerbated when dealing with church records where poor penmanship and only a tolerable level of education on the part of the clergy creates changes of spelling (this is also true with early church records in Britain). That of course does not explain the major difference between Kosty and Bundza, to do so we need to go back in the family tree as far as we can which leads us to Maria Kosztyo. This is probably the original spelling for Kosty. The information we have prior to emigration to the U.S. comes from a group of church records entitled "Slovakia, Church and Synagogue Books, 1592-1935", available on the FamilySearch website, plus the birth certificate of Charles Kosty Jnr, aka Vasil or Vassily or Basil Bundza , from which we know he was born at a place called Stakcin [1][2].

We do not have any dates for Maria but we do know from the baptism records that at some point she marrried Mihaly (Michael) Bundza and they had at least 6 children between 1874 and 1891. In 1868 Mihaly (Mike) Kosty (Kosztyo) was born, unforntuately no baptism record has been found for him. His naturalisation documents [3] state he was born 15 Oct 1868 in Stakcin. Whether Kosztyo was Maria's maiden name or if she was married before we do not know.

The piece that ties everything together is Charles/Basil Bundza/Kosty Snr's passenger list record in which he states he is going to stay with his step brother, Mihal Kost at 75 Tioga Ave, Corning, the known address of Mike Kosty at that time (1908). Why Charles changed his and his son's name from Vassily is not known. The family story has it that the change from Bundza to Kosty was to avoid confusion and trying to explain why your brother has a different surname to you whilst speaking little or no English. There are instances when Charles reverted to his "legal name", in 1912 when his sister-in-law Anna Kusnyir married, he was a witness and signed himself as Vassily Bundzia [4].

One other area of confusion is "where they came from", were they from Bohemia, Hungary or Austria or even Czechoslovakia? Were they Ukranian, Ruthenian? They definitely were not Bohemian nor Czechoslovakian, the former being in what is now the Czech Republic, the latter didn't exist until 1918. Autominously the village of Stakcin fell within the national boundaries of Hungary and formed part of the Austro Hungarian Empire from 1867 until 1918, but culturaly they probably considered themselves to be Rusyn or Carpatho-Rusyn [5] living in a region that crossed various national borders, borders that for centuries were forever changing. They might also have been refered to as Ukranian which apparently was a Polish term used to describe anyone of a Slavic background who were not Polish. It is safe to assume that they would not identify with those people living in The Ukraine which didn't come into being until 1922.

Footnotes:
[1] The majority of names have been "anglocized" in that they are minus the various accents etc found in their native language.
[2] Stakcin is in the Snina district of the Presov region of N.E. Slovakia. In Hungarian it is known as Takcsany. A link to the official Stakcin village website can be found in the links on the info page on which there is a history. You can also view that by by clicking on this link
[3] His name has been misspelt as Koist
[4] Yet another spelling variation of the name, when Joannes was baptised in 1874 he was listed as Bunga, when Charles was bapt. in 1884 he is recorded as being Vazul Bundra.
[5] Also known as Ruthenians or Rusnaks, a Slavic ethnic group that spoke Rusyn which is often treated as a dialect of Ukranian