I found a marriage record from a Polish Catholic Church in Chicago from 1900, and the name of concern to me was "Sakowicz." A Lithuanian linguist from a message board helped me out with this explanation: The name comes from Sako, "is saying." The surname became Sakas, which was Polonized to Sakawicz, which was put back to its current Lithuanianized form of Sakavicius. Interestingly, I believe they were from Kaunas! Anyway, my ggf (Sakawicz was his mother's maiden name) was Vytautus, which was Germanized to Witold, which was Americanized to William--lots of changes all over the place!