Fyoder, huh? I am kind of linguistically and phoenetically savy, but, you lost me.
We became Keans only because the English called us that.
In Germany, I have variably seen my family sign its name as Xulten, Seiferbach, Eisenach, and a lot of other place names.
I am told, during the AD 800s it was CYN in Greek lettering, and slowly morphed over time from Cune, Kune, Kuen, to Kuhn and the last change of the name were the umlauts over the u in the 1630s, which was latter changed to Kuehn with a French accent mark over the e during the early 1800s.
We are Huns, which goes a long way to explain why no one can spell our name correctly.